P: 3D Generated UVs produces poor result

[CallMeJim]

While I understand that using STL files from Thingiverse aren't guaranteed in any way to work in Photoshop... I have an STL file that used to work flawlessly in CC 2018 and is now utterly unworkable in CC 2019. I've got the latest version as of this posting date.

Model looks like this:
RackMultipart2019031633278jpa1-05125d8d-2521-43d7-b537-11b82c1d1945-119770193.png
(There's a bunch of domes).

In CC 2018, opening the file immediately results in a UV map that looks like this:
RackMultipart20190316128248kja-55f26a43-ea25-4eda-83ed-914b1fdb7d89-1570501865.png
The round parts are the domes, and it all paints quite nicely.

In CC 2019, opening the file results in a prompt to generate UVs. The generated UV looks like this:
RackMultipart20190316242161cax-bc63d5ee-8d7c-4296-b929-b327590dd4a6-342195605.png
It is unusable. The result is the same with/without the preserve appearance checkbox.

Additionally!!!!
RackMultipart201903164665ncfuu-2dd54c82-49ee-47fb-b664-40accca47aa8-1023566653.pngRackMultipart20190316966011tjc-98620e64-d05a-4eba-9d5b-0274d45ecce1-1766408482.pngRackMultipart20190316934661y9f-88ed5a82-f957-4f4c-ad40-14a622eb07e3-61583162.png
RackMultipart2019031629471sega-f7299b30-5179-483a-8c92-338c0c8cea03-1476156611.png
The exact same tool-tip appears for all 3 of these options in the Generate UVs dialog. 

[Jeffrey Tranberry]

Thanks. I've asked engineering to investigate.

[CallMeJim]

Problem also exists in CC2020, version 21.0.0 release.
Sample STL file: https://www.dropbox.com/s/the80k18zfhzopn/Dremel4000_Bot.STL?dl=0
When opened in Photoshop, select 3d > Generate UVs and observe the paint-on-3D result shown below:



Observe the result in the 2018 version of the software--the UV meshes are sensible and easy to paint on, and the paint-on-3d feature does not leave large jagged gaps and flyaway bits:


I'll become slightly concerned, as the 2018 version is approaching end of life and also can no longer be deployed in our enterprise environment, yet it remains the only viable way to use 3D models in Photoshop!