(bug report) solid tools not working as expected

when doing outer shell or union over two solids, the software could not combine solids correctly, leaving internal faces which causes problems afterwards. My guess is this is a bug. Attached a file of two solids right before outer shell or union operation.

Here is a video of what i tried: solid inspector, cleanup, intersect with model, etc.
https://drive.google.com/file/d/14cyqMkLuflPQPx7URnnK859McV1CwJB-/view?usp=sharing

Also attached the skp file right before outshell or union operationDemo of outershell bug 10-15 forum discussion.skp (354.1 KB)

Scale up by 100

scl-04

that’s helpful, thanks!