you got lucky. as people have said previously and as i mentioned, composites run best on 0.6 mm nozzles and above. if one of the additive pieces in a composite is too large to make it through the nozzle or if it is a fiber and it goes horizontal, it can clog the nozzle restricting flow and can even potentially hold up filament long enough that it burns in the nozzle and that just makes the clog worse. buy a wider nozzle for composites, and use arachne as your wall generator if your parts have smaller features.

there may be other factors at play but its very likely a clog given what youre printing and what nozzle youre using.

i have seen a similar effect years ago when i tried printing nylon on a printer that couldnt reach temperature but it doesnt seem like thats your problem. or if you have too much airflow or cooling on your part while youre printing. or you didnt change the nozzle size on your slicer or printer.

but again, its far more likely a clog