Let me say some things, none of which I can prove but I believe they make good sense.
Compost can be dangerous, my compost in my place is a worm bin. But it is full of probably thousands if not more kinds of bacteria, protists, fungi, viruses, etc.
This is why padawan warrior asked if it was composted long enough. When a compost is too
fresh, you can have larger populations of species of microbiota that are not desirable next to a fresh plant. FOR INSTANCE, when you have a pack of strawberries on your counter, and they start moulding, that can actually be botrytis.
https://www.google.com/search?client=firefox-b-d&q=botrytis+strawberry
Botrytis is the villain behind Bud rot. I guarantee you there is Botrytis in
my compost at times, but when you compost long enough other populations of microbiota take over and dominate. Properly composted material should smell pretty close to soil. My worms fuck shit up and I go from rotting material to soil fairly quick, compared to just compost.
I would not freak out and dose your plants roots with hydrogen peroxide, but if things keep getting worse before they get better, you might want to consider if your plants roots may be fighting a losing battle in that high compost-soil mix.
These are thoughts, do with them what you will.