mt76 incorrect limitations when using DBDC and vifs

Looking at a MT7916 from the favored vendor here. Device has 4 BSSIDs allocated to it.

From iw phy:

        valid interface combinations:
                 * #{ IBSS } <= 1, #{ AP } <= 16, #{ managed } <= 19,
                   total <= 19, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz, 160 MHz }

Yet hostapd reports an error (I think it was EBUSY) if I try to use a BSSID with both radios/phys.

My understanding is a device's pool of BSSIDs can be used by all attached radios as long as they're on different channels. Yet it appears the mt76 driver is only allowing each BSSID to be used once total for each device.

This is with kernel 6.12.40. I'll confess this isn't actually OpenWRT, but seems all of the main mt76 developers are here.

Start by reproducing the reported behavior on kernel 6.12.40 with the iw phy interface-combination output and multiple hostapd BSSIDs across both radios. Trace the mt76 driver paths that allocate and validate BSSIDs, then compare those limits with the device-reported combinations. Done means valid BSSID use across separate radios is accepted without the reported hostapd/EBUSY failure, with regression coverage if the existing test structure allows it.