weird weather radar indication on an A320 (picture attached)

[giggitygiggity]

Originally Posted by Capn Bloggs

AP2's not holding the altitude very well!

I know this is off topic but it looks like it's doing a pretty good job to me. 20ft is insignificant, the FMA shows it's in ALT CRZ which means it's in the soft cruise mode so the altitude can drift a little to avoid unnecessary trust and pitch changes to make the ride more comfortable.