Just confirming how this happened to me again.
`pythonexprs(\\\\\\\\\\\\\\
then you get an ever growing massive file that goes for gigabytes filled with slashes?!
Why this happen a lot I've no idea. Maybe it's because I struggle in vain try to use python in expressions (meaning unsuccessfully btw).

It's a major debilitating bug and a high priority.
The only solution to fix it is to cut and paste nodes from one file to another. Still lots of work get's lost, because by the time you realize it's happened to you again it's too late the file won't open anymore because it takes all your ram and then segmentation faults.
Sooner then later the time lost will easily exceed the value offer exchange.

{
name “vm_image_mplay_label”
label “MPlay Session Label”
type string
default { “” }
menureplace {
"`pythonexprs

Are you using the latest Houdini 12.5 production build?

Sorry I guess I should have posted that originally.

The build is 12.5.371, so that's yes to your question.
Why is there a known issue or something?

Well when and if I get a new version I hope this and many other problems have been addressed… as opposed to creating more stuff with debilitating problems.