I'm pretty sure that is false. Arex Delta locks on center. In fact it ships with smooth sided magazines.
The Arfcom reviewer repeats this all the while they show the actual magazine and it's very obvious that it is not a CZ-75 magazine. Literally, that happened at offset 03:40 in this video:
IV8888 says CZ P-10 magazine compatability, others said CZ-75 magazines. The OEM magazines are made by Mec Gar, who also makes OEM CZ magazines and aftermarket CZ mags.
Then in the TFB video a Rost Martin rep says straight up its CZ-P10 compatible.
So the video I was basing info on probably misspoke, hence my mis-speaking of the CZ-75 - but it is CZ magazine compatible, just the P-10 family not the 75's. Should've gone CZ-75 since they're far more available but whatever - at least you can get mags that are not proprietary.