Off taste after bottling

Gday guys,
I’ve been brewing for a while but for the last few times I’ve had the same issue. Before bottling the brew tastes fine but after time to settle and carbonate, I get the same flavours and after taste. I wouldn’t exsactly say it off but definitely an odd taste I can’t work out.
Everything get cleaned and sterilized. It’s been the same the last 3 homes but all different brews (summer ale, Belgium ale and Belgium larger)
Going with a rough 2x2x2 ferment, prime and secondry

Is it possible that the priming sugar cube I’m using doing this??
Am I somehow getting it infected??

Any help would be greatly appreciated

Can you describe the flavor/aroma?

And have you always done a secondary where you transfer wort?

How are you preparing the priming solution for bottling?