OK to Mix System Management Between EdgeMax and Unifi Controller?

Perhaps another daft noob question .... so forgive me, but here goes...

Background:

I've configured an ER-X with VLANs on switch0 as VLAN 1 and for IoT devices as VLANs 3, 4 & 7, eg Chromecast, Apple TV, Ezviz cams, with PVIDs and VIDs set per eth interface

The IoT devices are Cat 6 wired via USW Flex Minis with ports profiled for the respective VLANs.

I've then created "VLAN Only" networks in Unifi Controller for each VLAN, with firewall rules configured to prevent the IoT devices "leaking"

The ER-X has its stock WAN firewall rules created by the WAN+2LAN2 Wizard

Issue:

Everything appears to work fine, but when I audit the firewalls by giving my iMac a static IPA on any of the VLAN subnets, I can still ping the main LAN - which shouldn't happen if the firewalls were properly doing their thing per what I thought was a correct configuration.

Question:

Per the headed subject matter, is it OK to mix system management like this with the ER-X essentials configured on EdgeMax OS (ver 2.0.9), and the VLAN ports and associated firewalls configured on Unifi Controller (ver 6.0.43)? I've assumed it is OK as this is exactly what I do on other systems in other circumstances with ER-x's and UAPs. If it is OK I'll have to dive deeper into the firewall on the Controller and get it properly sorted in this case; if not, I'll scrap the Controller VLAN configuration of firewalls and reconfigure the VLAN firewalls in EdgeMax OS.

Thanks in anticipation.