RESOLUTION BUG

No, you're still chasing a red herring. A point is a physical size measure, from the days of lead typesetting.

An image file is just pixels, so many pixels high by so many pixels wide. It has no native size.

To translate pixels into physical sizes, you need to define a pixel density. The unit for this is pixels per inch (ppi).

Pixels per inch means exactly and literally what it says: how many pixels to a physical inch. The file itself is still just a certain number of pixels, but by determing how many inches to spread those pixels over, you have now set a size.

None of this affects the file itself. Ppi is just metadata, not a property of the file.

Please friends, understand, you are talking to someone who has been working with Photoshop for 15 years.

A mere 31 years for me friend. I wrote my first article for a magazine on Resolution way back in 1998 and I see it's still a topic of confusion today. 

I agree with Dave, file weight is an undefined term. We may have a language issue here but digital images have no weight! Or size per se. They are made up of pixels. The same number of pixels can produce a vastly different (if you must weight), size they take up on disk-based upon the number of color channels, bit depth, and other attributes like layers. This has ZERO to do with the fact that a 1000x1000 pixel document at 1PPI, 10PPI, 100PPI and 10000PPI are the same! Again, the only difference is a tiny bit of text (metadata) that can be used, repeat can be but doesn't have to be used, to define some 'size' outside of Photoshop! 

Facts:
1. Digital images don't have any size other than the space they take up on some storage media. This size varies by many attributes even if the document has the same number of pixels: bit depth, layers, file type and possible compression, color space. It's not worth even considering this size due to so many differences. Digital images therefore should be considered in pixel density. And for this discussion I'm going to limit this to one axis (let's say the long axix) and the image is 1000 pixels. 
2. An analogy is necessary to discuss the resolution tag in digital images. If I'm 6 feet tall and every stride I take is 3 feet, and my friend is 5 feet tall and every stride he takes is 2 feet, when we both walk exactly 1 mile, we walked exactly a mile. That I walked with less strides (resolution) doesn't change that I walked exactly 1 mile (pixels). 
3. The resolution tag places no role in the 1000 pixel document in this respect: 1000 pixels at 100PPI and 1000 pixels at 100PPI are the same: 1000 pixels. In fact you can take a document that has 1000 pixles with a resolution tag of 100PPI, duplicate it and change the resolution to 1000PPI and the two are identical other than for metadata such as this resolution tag. And of course metadata like date/time the document was created and so forth. The two documents are 1000 pixels and the tag has no role and does nothing at this time. Set it for anything you want, as often as you want, it's the same digital image at this point. 
For all intent and purposes, the resolution tag plays no role. The number of pixels does. But wait you say, "I want to output the 1000 pixel image". To a print or on screen. OK, now we have a new size to consider! Let's work with a print. Computers are not too smart, they have no idea what you wish for a print size until you tell it. They do know you have 1000 pixels to use to make the print. What size print do you want? The answer comes about when you divide up the pixels you currently have (more about what you might have later) for this print. Now size can be inches, feet, meters, miles, CM, MM you get the point. Let's stick with inches for this story. You have 1000 pixels and the resolution tag is set to 100PPI. You simply need to understand simple math (division) or have a calculator once you accept you have 1000 pixels. At 100PPI (the tag), a print could (repeat could be), 10 inches. If the tag is 1000PPI, you're going to end up with 1 inch if you allow the computer to provide that division of your pixels. If the resolution tag is 23PPI, the size would be 43.4783 inches (here's where a calculator is useful). It's not if the tag is in MM or CM, or you alter the tag value. But in every case, the data is 1000 pixels. That is the critical number to know about first. The other number can always be changed so software can at this point understand a potential size for output. 

Work in pixels. Have a calculator nearby if necessary. Pretty much ignore the resolution tag until, if, you need to output that data and you require a specific output size. Understand you can allow software to interpolate BASED on the resolution tag. If the tag is 100PPI and you tell LR you want 10 inches, the results are quite different than if the tag is 1000PPI and you tell LR you want 10 inches. You are in control. The software only looks at the tag if and when you tell it to look and use that tag to produce some size with the pixels you have.  

Of course, had you read my PDF from the first answer here, I would not have to paste these facts above. Or this fact from Dave which is absolutely spot on, correct:

Image resolution (ppi)  has no impact whatsoever on the image file size on disk. The value 72ppi and the value 300ppi does not increase the file size on disk, it is just a number stored alongside the image data.

Bottom line, as you've described (as best you have) your 'issue', the facts are, this isn't a bug in Photoshop.