I've experienced a bug with multiple merchants in Skyrim. If you get the merchant above 42750 gold, say, with training, you'll run into a problem when you sell to them. After the merchant's gold is reduced to 42750, you'll no longer gain any gold from selling to them. They will still take your item, and no warning prompt is given.
I've experienced this bug with both Florentius and Tolfdir. Someone else has experienced this with Babette.
On that thread, someone mentioned that merchants get bugged once they go above 30k gold.
I already have unofficial legendary edition patch. So I wish to ask the following questions.
Does this apply to all merchants?
Do the merchants break above 30k gold, or above 42750 gold?
Why does this occur?
Can this be fixed?
Are there anything else I should be careful about when dealing with merchants?