I had an Excam BTA-90 ( Italian copy of the CZ-75 compact. Now goes by EAA. Pistol made by Tanfoglio.)
It broke COMPLETELY at the exact same place! Importer rep told me it wasn’t uncommon. Heat treat issue.... Mine had the hard chrome finish.
I sent it to them and they fitted a new barrel, slide, and did a complementary trigger job. Return shipping, too. New slide had an integral sight rib the length of the slide.
I’d send it to CZ and let them replace the slide. It’s a manufacturing/design flaw, so it’s their baby!
They even honored the warranty on an Armscorp Turkish made (Huglu) 20ga s/s that I sent back for doubling. Took 11mos, but they honored the warranty by sending me a NEW GUN!
CZ had taken over the importation of the shotgun. Now it’s called a Golden Pheasant.