The Latin word for "report" is refero, referre, rettuli, relatus. At first, I thought that rettuli, with 2 t's, was a typo, but it actually appears that retuli, with just 1 t, is the uncommon form in comparison.
This seems rather strange to me, because most of the compounds of fero do not seem to double the t. For example:
defero, deferre, detuli, delatus
effero, efferre, extuli, elatus
offero, offerre, obtuli, oblatus
infero, inferre, intuli, illatus
Why is refero an exception? Additionally, what instances are there of Latin writers using the more uncommon form of retuli instead of rettuli?