frosted ice won't melt

What I expected to happen was that my frosted ice would melt

i thought it wasn't a problem and it would melt soon

But what happened was that it isn't melting it just don't want to melt even if you relog

i runned over a river (at night ) with my frost walker 2 (diamond) boots

Steps to Reproduce:
1 Do /time set night or wait until its night just make sure its night
2 Walk over water with frost walker (you don't have to make sure which level it is
3 and now you have melting ice that don't want to melt

I don't know if this is an real minecraft mechanic or a bug but it is weird if this is a minecraft mechanic