Getting back to the original question, something similar happened to me. I went to make my confession to a priest I did not know instead of my ususal confessor (just more convenient at the time). Because I am a convert I read a lot, and my book about confession says to say a little about yourself first, just to put your confession in a context, so I started by saying that I was having a lot of doubts about the Church, and had (as well as going to Mass etc) attended a few services at the Unitarian Church. Well, twenty minutes later he was still going on about this, and had even threatened not to give me absolution if I didn’t agree not to go again! I said how could it be sinful to have genuine doubts, and that I hadn’t realised it was a sin at all before I’d come into the confessional. Eventually we compromised, and I agreed I would try not to go again. But the thing is, I asked him (unbelievingly) if this was a “mortal” sin then, and he said (reluctantly) “no”, so even if it had been a sin, it wasn’t one that needed to be absolved by a priest!!
The funniest bit though was at the end. I had gone in the “normal” half hour “confession period” and had been in there twenty minutes. I could tell he was getting ready to wind things up, and so said “But I haven’t told you my real sins yet!!” and he said “There isn’t time, but the absolution will cover them as well”.
I discussed this later with my usual confessor, who said that though irregular, the absolution was ok, but who was very surprised at the threat to deny me absolution. He said when he was at seminary they were taught that this was such a serious thing to do that if you ever found yourself doing it more than once, you should look to yourself and see where you were going wrong.
In mitiagtion though, I do still like the priest who did it (he did say what he did in a very sincere and caring way), and I found out that later that he had only recently been ordained.