The text is drawn behind the highlight.
I only have this issue with calendar widget.
I can workaround the issue by adding transparency to the "hover" part of "viewitem.svg" in the plasma theme file.
this is a reddit post about this topic: https://www.reddit.com/r/kde/comments/t64uah/hi_i_installed_this_plasma_theme_everything_is/
STEPS TO REPRODUCE
1. Apply Unity Ambiance shell theme
2. open calendar widget.
3. No text in Today's date.
No text in Today's date.
'4' in Today's date.
Operating System: Arch Linux
KDE Plasma Version: 5.24.2
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.3
Kernel Version: 5.16.12-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-6400 CPU @ 2.70GHz
Memory: 7.7 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 750 Ti/PCIe/SSE2
A possibly relevant merge request was started @ https://invent.kde.org/frameworks/plasma-framework/-/merge_requests/471
Git commit bb2bc5827f43dfce8f217b7c4370acaec0dca032 by Ivan Čukić.
Committed on 06/03/2022 at 22:15.
Pushed by carlschwan into branch 'master'.
Calendar: Draw highlight below the text
The highlight is drawn on top of the day which makes the text not
visible when the users use themes in which the highlight is not
This sets z order of the highlight to -1 which makes it painted
below the text.
M +1 -0 src/declarativeimports/calendar/qml/DayDelegate.qml
Thank you for the consideration. Note that the "months" and "years" sections of the calendar wigdet also have the same issue: the current value indicator doesn't show the text...