What happens when you encounter - "per policy or regulation" but no policy or regulation exists?

The onus is on the person citing "per policy or regulation " to provide it, cant provide it, it does not exist nor will it be considered.
and that works both ways>

"SGT you need to submit an original ink signed copies, per regulation photo copies are not allowed"

Sir, what regulation is that?

"Sir, here is my form, yes I know its a copy, AR-123 says clear readable copies are allowed, no ink signature required"

I was gigged on a technical inspection because I wasn’t holding a wrench like a picture showed when the para stated hold the wrench in a way that ensures positive control through it’s use. I did a DA 2028 requesting clarification. A change page came out clearly starting that pictures in the technical manual were not the definitive guidance.

This happened over 5 years ago and I know the regulation has changed since, APFT - I failed an APFT (missed the run) and was informed by the AO that I would take another one for record in July after Annual training, I asked if I could take one before Annual training instead, was told yes and if I passed would not have to worry about the one in July. So I had a E-5 and an E-6 assist me with taking the test, the E-5 was to timer since he was on profile for his knee that was injured in country, the E-6 scored it and even ran with me on the run. I passed. Filled out the paperwork and submitted it, then the S1 OIC said the test was no good because the regulation says that a person on profile can no administer an APFT. I asked for a copy, never got one. Pulled a copy and read the regulation myself and did not see it, asked the S1 OIC if they could show me where it was because I didn't see it. Was told it was a Battalion policy that a person who has not passed their APFT can not administer one, asked for a copy but never got one. This went back and forth for a few months then in July when I took to APFT again with the new Battalion commander, he asked why I was taking it again since he was aware that I took it just a few weeks before. I informed him of what I was told. Then a few weeks later a battalion policy was signed and published with a back date of 6 months.