Did you look at the evap coils? Low charge sometimes causes bottom 1/3 of coil to ice up or run colder and accumulate pre-icing condensation more than the upper 2/3 of the coil.
What's your SH, SC, and amp draw?
I'm thinking one if not two problems.
1 - low charge
2 - txv powerhead dead, and possible low charge if icing present