I've recently updated my environment to use MCUXpressoIDE_10.3.0_2200, MCUXpresso_Config_Tools_v5, and SDK_2.5.0_LPC54608J512.
I noticed that config tools now gives me an warning which seem to be an error, and which was not present previously!

When I investigate further I find that the pins I have routed for FLEXCOMM1 do not appear to be recognized as valid I2C pins in V5.0.

The pin options provided by the tool are shown below, and the pins I use are clearly missing.

The tool does seem to produce the correct code output, but this warning is concerning and I presume a bug which needs to be resolved.
Please let me know if the warning can be safely ignored or if there is a fix for this.