There is no zap etiquette. Use your sats as you see fit. It is money, afterall.
Errors happen for many reasons, most of the time they are temporary. Sometimes it's an error on your side, sometimes the other.
Discussion
This? This is what I get, is it me? #asknostr
Is this from the primal app?
If so, there's a setting somewhere for "default zap message" or something similar. You should be able to change the message to something shorter or remove it completely if you want. I'm guessing here but I have a feeling that will fix it.
#nostrability ... compatibility issue maybe?