Been wrestling with external control settings on MPPT chargers myself, particularly when integrating with monitoring systems via VE.Direct. The way Victron handles remote control can be genuinely confusing if you're not familiar with the protocol stack.
From what I've found, the issue usually crops up when you've got your MPPT (I'm using a 100/20 in my setup) talking to a Cerbo GX or similar hub. The charger defaults to accepting external control commands once it detects a compatible device on the VE.Direct line, which can cause unexpected behaviour if your hub is sending instructions you haven't explicitly configured.
The solution typically involves diving into the Victron software settings. You'll want to check whether your hub is configured to actively manage the MPPT, or if you're just looking to monitor it passively. The VRM portal and your local Cerbo interface should both have relevant settings buried in the device configuration menus.
What's your actual goal here? If you're just after monitoring without the charger responding to remote commands, that's a different configuration than if you want scheduled charging control based on battery state or load management. The distinction matters quite a bit for how you'd disable external control.
Also worth checking: which software version are you running on both the charger and your hub? Victron's firmware updates occasionally reshuffle these settings, so knowing your versions would help identify the exact menu path.
Has anyone else had the charger misbehaving when connected to their monitoring system? What did you end up doing?