Maybe... look at the fees on each. If they're the same then I can't think of a reason to consolidate (or to not consolidate). If they're different then that's the reason.
I've just moved mine from Aviva to Vanguard for the slightly lower fees.
The two old ones are at 0.35% - nothing being paid in. Total value is less than £20k
Current employer one is 0.4% and is being paid into. Total value is just over £60k
I have three pension pots with Aviva (one current) and two from previous jobs.
Is there any reason to consolidate them?