[BUG] Photos reset to default when switching from Grid mode to crop overlay via shortcut key "R"

I suggest you post a bug report in the official Adobe feedback forum, where Adobe wants all bug reports and feature suggestions: 

https://feedback.photoshop.com/photoshop_family/categories/photoshop_family_photoshop_lightroom

Be sure to include the first ten lines of the menu command Help > System Info.  Provide all the details, rather than linking back to this thread -- experience shows that Adobe developers tend not follow the links.

It's unlikely Adobe will take any direct action, since the behavior is not easily reproduced. However, having the bug report there is important in case someone else comes along with similar symptoms. When a pattern starts developing, Adobe will pay more attention.

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I've got two recommended troubleshooting steps:

1. If you're using a mouse with a mouse utility (e.g. Logitech), try a generic mouse with no mouse utility (or at least uninstall the mouse utility). The double-click of the middle button shown in the screen recording is very suspicious.

2. Try resetting LR's preferences: https://www.lightroomqueen.com/articles-page/how-do-i-reset-lightrooms-preferences/. LR sometimes soils its preferences file, and resetting it can fix all sorts of wonky behavior.

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Close examination of the video suggests a problem with Synchronize, which twice fails to copy the correct value of Exposure from one photo to the two other photos (at 0:44 and 1:13).  Also, Entries in the History panel are missing or incorrect.

Here are the events that change Develop settings:

0:06 Develop invoked on photo 0989. It has Exposure = +1.32, and its History is:

0:19 Synchronize of Exposure (+1.32) from photo 0989 to photos 0978, 0984.

0:27 Exposure of 0989 changed to +1.34, and its History is now:

0:28 Exposure of 0989 changed to +1.14.

0:34 Synchronize of Exposure (+1.14) from 0989 to 0978, 0984.

0:44 Develop invoked on 0978 and Exposure = +1.34, not +1.14 -- a bug.

0:55 Develop invoked on 0978. Exposure changed from +1.34 to +1.14.

1:02 Synchronize of Exposure (+1.14) from 0978 to 0984, 0989.

1:10 Develop invoked on 0989.

1:12 0989 appears dark, with the Exposure slider at 0, rather than +1.14, with no numbers appearing to the right of the Basic sliders (a bug😞

1:13 The image gets a little lighter (though not as light as it was before), and the Temp and Tint sliders adjust to 5800 / +7. The image also gets cropped a small amount (pay attention to the bottom edge). The most recent entry in the History panel is Multiple Settings rather than Synchronize (from 1:02), and the second most recent entry is Exposure -0.02 +1.34 rather than Exposure -0.20 +1.14 (from 0:28). (A bug.)       

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Are you using a mouse with a utility that lets you assign functions to buttons (e.g. a Logitech mouse)?  A couple of times in the video, it shows you are double-clicking the middle button, e.g.

Are you deliberately double-clicking the middle button?

(The screen recording utility is great -- what is it?)

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There is a keyboard shortcut for Reset: ctrl+shift+R / cmd+shift+R which is almost certainly what is happening.

This is very similar to the keyboard shortcut for resetting just the crop (ctrl+alt+R / cmd+option+R).

I can imagine those two getting accidentally switched (as a pure typo, when working in haste perhaps) but it's harder to see how "R" and "ctrl+shift+R" could get confused with each other - unless the keyboard has some intermittently sticky keys, or something sometimes resting on the corner of the keyboard there, or unless there are modifier keys getting "pressed" by other means e.g. via buttons on a graphics pad stylus, or some other controller.

I can't reproduce this behavior - can you provide more details about  your system,  version of OS and Lr? Can you make  this happen or is it random?