This bug just randomly happened on my vanilla minecraft 1.14.3 server, so I thought maybe updating to 1.14.4 would fix it but it did not, sometimes water only flows 4 or so blocks and sometimes it doesnt flow at all, which has broken my mob farm. I have only experienced this bug in this area, even if I place down a bucket of water here this happens I really have no way to fix this that I could findĀ
while this bug is being fixed a temporary fix might be to update the water just place a block next to it and it should fix