[GAP Forum] groups of order 512 inconsistency

[Benjamin Sambale]

Dear GAP people,

I noticed the following unexpected behavior in GAP 4.11.0 (and some 
older versions):

G:=SmallGroup(2^9,261648);;
H:=Image(IsomorphismPermGroup(G));
Size(Center(G)); #returns 4
Size(Center(H)); #returns 8

The same happens if we convert into an fp group. Other groups of order 
512 and 1536 are affected as well.
I know very little about pc groups, but my guess is that the 
presentation of G is somewhat inconsistent, although the problem does 
not occur in MAGMA.

Best wishes and stay safe,
Benjamin