Ice not forming

i dont know when this started happening (or not happening) as I haven't been to my ice farm for a while, but have just been now and ice is not forming.

my ice farm is built on a glacier biome and usually when I have finished harvesting one side of it the other side is ready to harvest again (ie ice has reformed) but now no ice is reforming.

I broke some of the naturally generated ice and filled in the water and that didn't turn to ice either