The bug
Water freezes even if randomTickSpeed
is 0. It'll convert to ice in any snowy biome when next to another block; it does not need to snow for this to happen, but does need to be the highest block in the world.
Linked issues
is duplicated by
relates to
Attachments
Comments

But I expected it to just stay water, not freeze, I thought, since dirt(to grass) is randomly ticked and effected by the gamerule, that water(to ice) who are kindof randomly ticked, that it'd be effected by the gamerule too

has a developer said that randomTickSpeed is intended to not affect lightning strikes and weather checks like this?
1. Lightning is completely unrelated here
2. This only effects water next to another block in snowy biomes, no need for it to snow
That it's not mentioned, doesn't mean it's intended, I'll wait for a developer to reply
Confirmed for 18w30b
Confirmed in 1.16-pre5.
Confirmed for 1.16 Release Candidate 1
Affects 1.16.2 Pre-release 1

In 1.16.1
Can confirm in 21w03a.
Confirmed for 1.17.1.

Major bug for mapmaking.
Affects 22w18a
Can Confirm 1.19.3 Release Preview 3, affects map making negatively.
Water is not ticked by random ticks.