Twice I have had problems with crooked chokes shooting off POA.
In one case, some aggressive "polishing" of choke, making it more concentric, helped a lot. However, still needed to find load(s) that did give centered patterns. Was successful, with at least a small number of loads.
On one barrel of a cheap Spanish double, pattern was both very irregular and off center. Finally found a single load that gave nice even and tight (80+%) patterns from that barrel, as well as 70+% patterns from other barrel. Used that load happily with that gun for many years.
Niklas