In python scripts, editing as UTF-8 Python, some '_' characters are not displayed (so they appear as spaces). If (an unchanged) file is reloaded (F5) then they re-appear and, I think, stay there.
This behaviour is a scrolling-window fault. If a view is part-way down the document, and then scrolled to show text higher in the file, and the line 'just above' the original view had underbar characters in it, they will probably scroll onto screen as spaces not _ . This looks to be a slightly small (off by one?) redraw zone when brining lines back into view.
Could you please attach a screenshot?
If this happens only at the last line, then this is bug 393616.
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Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days, the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging If you have already provided the requested information, please set the bug status as REPORTED so that the KDE team knows that the bug is ready to be confirmed. Thank you for helping us make KDE software even better for everyone!
Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!