Yeah, thanks!
You know, looking at how it behaves (all is true) I don’t think I should want to use the bounding box :) I am just fine with hitting E to access Free Transform tool which is *almost* works like the bounding box, but easier to call and glitches less.
I use Scale, I use Rotate, some other tricks.
The only case for me to turn the BBox is to resize an area type text :)

Regarding the issue... I made some experiments with these shapes.
I took a coin’s top face (a compound path) and rebuilt it: applied Exclude, Ungroup, Uncompound and Compound back. The result looks the same, but gets rotated with bbox just fine... until you rotate it with Rotate — this seems to reset the bbox immediately.
Once rotated with Rotate, the bbox always get reset on rotating a compound path. And if a group has a rotated-with-Rotate compound path in it, it has the same problem.

What a nonsense.
Thank you all for raising this up!

Egor, i made a sample file, hope that will help.

Frankly, i can't imagine the way to work with illustrator without using bounding boxes — it's the main tool to operate with any object, you can't do most transformations without using bounding box :)

Serge, Dan, everybody — can someone here share a test file for the developers to look at? 7 users, not a one file to dissect. It does not have to be the whole project you are working at, just that piece which glitches out!

I’d certainly provide it myself, if I had one, but I just don’t use bounding box at all, and have no idea if it gets reset or not. I will try to catch it though too.

I've experienced this but for a long while, in different variants. First it was about compound objects while using rotate tool (somehow rotating with rotate modifiers didn't reset bounding box), now it's about groups too. Absolute nightmare to work with.

I've got the same bug on Windows 10, Illustrator 25.2.3
The bounding box doesn't rotate with the object rotation. It seems like it's automatically resetting.

But it works for text though. So strange.

Problem still persists (illustrator v 25.1)

I am using CC 25.0.1 and need to resize a circle from the center along a diagonal line and cannot do it. When I rotate the circle so that the anchor points (and I was hoping bounding box) match the diagonal line, the bounding box automatically resets. This did not happen for me in CS5. If I change the circle into an oval and rotate, then the bounding box rotates as well. But for a perfect circle, which I need to retain, I cannot scale in the direction I need.

Mac os 10.14.6, Illustrator 24.2 (but the problem persist for a while, probably since basic shapes were introduced, but i'm not sure)

Bounding box of any compound path composed from any number of shapes or freehand paths (even just one) being rotated with Rotate Tool (R shortcut) automatically resetting. If compound path constructed of basic shapes only (ellipses, rectangles, etc) and rotation is applied by dragging on a corner rotation widget bounding box behaves normally (aligned with rotaton).

Almost the same with group bounding box with one big difference — bounding box of a group containing any number of basic shapes stays aligned with the group (no matter if i rotate it with Rotation Tool or by the corner rotation widget dragging). When group contains any freehand path any kind of rotation automatically resets its bounding box.  

My actions step by step: pen tool, draw a path freehand, draw second path freehand, selected both paths with Selection tool (shortcut V), made compound path (shortcut cmd-8), select Rotate tool (shortcut R), rotate random angle, select again with Selection tool — bounding box looks as if it been reset. (Screenshot 2020-06-30 16.03.17)

If i rotate this compound path not with Rotation tool (R) by dragging on the corner (that with little arched arrow modificator) boudning box will look aligned with rotation, as it supposed to. (Screenshot 2020-06-30 16.03.26)

But if i use Rotaton tool (R shortcut) after that even once bounding box will be immediately and permanently reset.

Damn' that's annoying! "reset bounding box" does not fix it. Completely spoils my workflow and has now cost me several hours of wasted time. Running 24.03 in macOS 10.15.3 on a 27'' 2017iMac.
Oh yeah - the bug "spills over" and is now also present in v23.
- just uninstalled all versions, deleted the prefs in "Library/application support" and "User/Library/application support", then reinstalled. No change.

I was struggling with this as well. What I stumbled on for a fix was click on "reset bounding box" agan it stays constrained with the shape. ...Go figure.

I've had this problem off and on for a while. This is the only post I can find about it.

This is an old bug. I had it in CS3, ten years ago. Guess it's one of those flaws/bugs that will be around forever.