ok, I had a closer look at it :
connection by midi din digitakt -> preenfm
digitakt send midi clock.
with bank select 0, i then send fast program changes, everything is fine,
with bank select 1, after some program changes, it crash with the same error message I sent previously, even when changes are slow (~1/second)
with bank select 2 or 3, after some program changes, it just freeze, without error message.
without clock send, the crash are less frequent, but still happen..