Created attachment 155836 [details]
Window in plasma 5.26.90

SUMMARY
I have windows set to display with no border. Upgrading to plasma 5.26.90 causes windows to display with a border.

STEPS TO REPRODUCE
1. In plasma 5.26.5, set window border size to 'Theme's default (No Borders)' in window decorations
2. Upgrade to 5.26.90

OBSERVED RESULT
Windows display with a border

EXPECTED RESULT
Windows should display without a border as in 5.26.5

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.26.90
KDE Frameworks Version: 5.102.0
Qt Version: 5.15.8
Kernel Version: 6.1.8-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 12 × Intel® Core™ i7-8700 CPU @ 3.20GHz
Memory: 31.3 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1080/PCIe/SSE2
Manufacturer: Notebook
Product Name: P7xxTM1
System Version: Not Applicable

ADDITIONAL INFORMATION
Switching between 'Theme's default (No Borders)' and 'No Borders' and then clicking 'Apply' causes the window borders to disappear and then immediately reappear.

Downgrading to 5.26.5 reverts to windows displaying with no borders.

Global theme: Breeze Dark
Application style: Breeze
Plasma style: Breeze (Follows colour scheme)
Colours: Krita Dark
Window decorations: Breeze