If you use Glow lichen to stop water from flowing like you would use signs or pressure plates the water acts different as shown in screenshots. The top water block flows to the other side. The Glow Lichen affecting the behavior is the one to the left. The bottom one doesn't matter what block it is.
MC-250408
Water can flow the wrong direction next to glow lichen
Open
4
(Unassigned)
Confirmed
Platform
Low
Block states
1.18.2, 22w16b, 1.19, 1.19.4, 23w18a, 1.20.4
Retrieved
Can confirm in 1.19. The "Environment" field of this ticket can be removed since this issue isn't environmentally exclusive.