Manually written captions is sometimes having the (+) as gray while the space is available

On the latest version of Premiere Pro 2023

When I edit a part of my video I go ahead and type its captions with first switching the workspace. However sometimes the (+) icon for adding the next caption is gray even though the space is available. I use the "Subtitle" captions. This especially happens when the space was occupied at first, I move the play head to an empty space but it doesn't update.

The workaround I could find is not selecting any videos and moving the play head to an empty space before switching the workspace.
I wasn't using an updated version for a long time and I can definitely say that this wasn't an issue in Premiere Pro 2021.

This bug slows me down a lot since I add my subtitles after editing a specific section first.