Please enlighten us as to the OEM limits for the abnormal start you are referring to.
If I had such a start I would be extremely concerned and abort the start well before idle.
This is a windup surely.
I like the play on words "this is a windup surely"
One of the reasons that you may not get the fan turning during start is that the blade tips have managed to windmill backwards jamming the tips into their fan case. The start sequence turns the non fan compressor rotor and its only the air from this rotor flowing through the aft turbine that begins to add torque to spin the fan. Until the engine actually stabilizes at idle the rotors are not well matched in RPM differences (not a biggie since you aren't expecting much power).
The key to a good start is what the EGT is telling you (burner stabilization) and the engine reaching a stabilzed (at idle) match between spool RPMs.
On the other hand if there are any concerns they would be stated in the FCOMs etc. by the manufacturer
Perhaps there is a corralary somwhere in the turboprop world of starting vs the prop speed