Wierd Alpha-ed line

in Bug reports

I don't remember since what version but it's new, i sometimes get a wierd 1/2 length line that has a wierd behavior. It's painted as if it's an kind of not 100% opacity pen. I can fill bucket to fix it but the pen is still not painting right afterward (forgot to show it on gif).
It does that with my wacom and my mouse. On windows 10.
Comments
On windows 10
PyxelEdit 4.8
If you could email me a document that has the issue that would help a lot in debugging it (support@pyxeledit.com).
I tested it with 16x16 tiles, as well as 32x32 tiles, and thinking it might be an even sized tile error I also tested it with 33x33 but all tile sizes successfully reproduced the bug.
I tested the following versions as reproducing the bug on Windows 10 64-bit:
I tested the following versions as unable to reproduce the bug on Windows 10 64-bit:
Reproduction steps:
Here's a gif of the bug happening with said repro steps: