Why do you feel the need to question my comments and knowledge? I made a statement for the OP.
I’m going to remain polite and just let you be. Good night.
I beg to differ. As a mechanic for 40+ years, I’ve seen plenty of burnt intake valves behave the way the OP describes the symptoms.
A flat exhaust cam lobe will also cause a spit back through the carb.
A compression check is needed.
Many good answers above.
‘Another might be a burnt intake valve causing a backfire into carb off idle or under load. Take a compression check.
Good luck with your findings.