The magnetism provided by Avantix▸ machines is not on par with those issued by ticket machines in ticket offices and TVMs▸ and hence the magnetism wipes out quicker - for instance, get an Avantix ticket from a guard for a London all zones travelcard. Do not put it anywhere near a mobile phone or credit card or anything that could possibly remove the magnetism... then go around trying barriers on the Tube - should wipe out within about 4 valid reads... whereas a TVM should last the day.
Isn't this a justification for
FGW▸ (or whoever) to use a different supplier as the existing product isn't "fit for purpose "?