I thought mine was stalling too.... The spikes grew but no flowers developed for AGES! I got quite worried its my first Onc. and first spikes
I decided maybe it was water as she's a thirsty one compared to Phals etc. so I tried soaking for an hour at watering times in a bloom fertiliser to give it time for a good drink, and saw growth renew within a week!
Whether it's the ferts, the watering time or just the weeks and weeks I watched it doing nothing before this I'm not sure
but within 3weeks of changing my habits I'm waiting for flowers to uncurl any day now.
Just make sure it's not still too wet before u water it again each time