QPlainTextEdit adds giant block of nothingness if contents are updated and element is not visible

Despite this bug listing Qt versions 6.4.2 and 5.15.11, I've actually noticed this bug for probably 5 years now, it is a very longstanding issue.

What seems to happen is that a QPlainTextEdit object is updated when the object is not visible, e.g. it is inside a tab view and the user is on a different tab. If the object is visible, it seems to update fine, here is an example:

If, however, it is not, then when it becomes visible again, there is this giant empty section which is useless and actually has nothing in it:

If you have a serial device, you can use this to replicate it: https://github.com/thedjnK/AuTerm (Note: use v0.24a or older only)

I did originally think it was an issue in my code, but I created a brand new application earlier this week which just tallied numbers up and output them to a QPlainTextEdit and this is where I found out it isn't an issue in my code because the same thing happens there too