Visual glitch of flagging a black whole

[avi12]

Debug info

Version: 1.0.9
Motion: true
Supports WebGL: true
Feature Phone: no
Standalone Mode: no
Screen Width: 1920px
Screen Height: 969px
DPR: 1
Device Memory: 8
Concurrency: 8
UA: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.75 Safari/537.36

Describe the bug
Every now and then, I flag a black hole and then some other one (usually nearby) becomes white (still flagged).
Visual representation: (Bottom row, 3rd column from left)

It is worth noting that it's not unique to Chrome on Windows. It also occurred to me while playing in the PWA version, as well as on Android in the app version.

To Reproduce
I don't know, seems to randomly happen.

Expected behavior
All the flagged black holes should be colored in blue, and stay as blue.