The group I worked for had their own choppers but hired Chieftain, Baron, or Aerocommander from an airport operator when needed.
On a SPIFR flight in a Chieftain, I reached cruise altitude, trimmed it, and engaged the AP. Very soon after, it developed a roll oscillation , increasing with time. Several retries later, I had to disengage it and go manually - not particularly legal. On return to base, I told my (non-pilot) supervisor that I thought the roll rate sensor was U/S. He said he would tell the owner and get it fixed - I was due to fly it again in 2 days.
Sure enough, 2 days later, with assurances it was fixed, same thing happened. On return I wrote it up in the MR, and immediately got a phone call from the irate owner who claimed he had spent $3000 fixing it the first time. Horsefeathers. But at least now, he had to fix it.
The owner, some years later, was in court over charges of giving kickbacks to my supervisor. Supervisor also in court.