cold fusion 2016 is locking files randomly

And when you say CF "hangs", can you elaborate? Do you mean no other CF pages can run, at all? Even ones that have nothing to do with that "locked" file? How about the CF Admin?

It just makes a really big difference diagnosing a problem limited to that ONE problem (which could affect other pages also interacting with the "locked" file), versus a problem of ALL of CF hanging up.

It will help us also to know what you mean by and how you know that the file is "locked"? Perhaps it will be in an error message, as BKBK has requested you share. But maybe instead it's just a perception you have. Again, more details will help us help you.

Finally, you say you are on CF2016. Can you confirm what update to CF2016 you are on? The last was update 17, released in Mar 2021. I'm not saying you WILL find the problem caused by being on an older update, or that it would be solved by a later update, but it may. (Of course, one should always be aware of the implications of applying an update, and that update 17 in March 2021 had some breaking changes, in the name of security, so don't just throw the update onto prod, of course, if that may be all you have.)

Beware also that with CF2016 no longer getting updates, one really should no longer be running on it or older CF versions. Only CF2018 and 2021 currently get updates, and have gotten 2 more since then.