Ph probe gone bad

[Bob Escher]

hi everyone
And no I haven't yet
My Apex ph probe went from yesterday 7.60 ( was always off) to today at 2.6 that quick
Has it gone bad I generally recalbrite it every 6 months I got about 2 months left
I will recalibrate it but wondering why it dropped like that? ( I have a Hanna checker that confirms ph is ok at 8.1

Thanks