Hey Ziggy,
This would be the case if with your relays, you have connected the router and the dust collection on ‘load-1’ and/or ‘load-2’ instead of ‘tool-enable’ pin. Is this the case? In your G-code example, the “M3 spindle forward run” command is before the first “G4 Px” pause and the “M8 workpiece flood coolant on” command is after this pause.
The ‘load-1’ and ‘load-2’ outputs on Buildbotics & Onefinity Controllers are for workpiece coolant because they are switched on with the commands “M7 mist coolant on” and “M8 flood coolant on”. However turning the milling motor on is done with “M3Sxxx” command. On Buildbotics & Onefinity Controller, the latter works out-of-the-box for ModBus-controlled VFDs, and for milling motors on a relay, it is supported by them via the ‘tool-enable’ pin, which is switched on by “M3Sxxx” too.
By the way, the spindle coolant pump always has to be controlled via a relay attached to VFD, not to CNC Controller. This is because the VFD knows whether the spindle runs (and needs cooling) or not.
So if the relay with which your router is switched on and off is connected to ‘load-x’ pins of CNC Controller (instead of ‘tool-enable’ pin), then it is switched on with M7 or M8 commands instead of (correctly) M3Sxxx – thus the first pause is not honored then.