I bought a MX300 525GB and updated the Firmware to M0CR040 and i'm using it in a PS4 Pro.
The problems is that downloads get interrupted all the time, I think it's in especially while downloading multiple files and/or downloading while in standby mode.
I updated firmware because without it i had even more problems, loading game or savegames created errors too (e.g. in XCOM2), new firmware fixed that.
Don't have errorcodes, sorry.