Not bugs - if their adapters start sending random crap over CANBUS, what can I do?
If their adapter dont work ok J1850-PWM (what fords use for the diagnostic bus) what can I do? people instinctively blame the app, rate it bad or (in the best case where I can reply) send an email.
The hardware they copy is buggy, it's well known (ok you may have to search a bit for 'clone ELM237 buggy J1850' etc, but you'll get there if you dig)
The software has been made to work with the buggy adapters, but there's only so much you can do. If you send '0100' and the adpater goes '0102' to the ECU, wtf can I do?!