maybe? there's no vege time given for these.. so no idea.
not all plants grow at same speeds, though many will even out as they get older.. some stay small. A few days difference early is more obvious than later on in grow.
A large pot relative to pot size can be part of it.. and, not just due to difficulties related to watering it properly.
whic leads to he last thing.. proper irrigation habits... and substrate ... with coco you still need perlite for proper darainage and o2 penetration 70/30 is enough because it holds less water per volume than typical soil / sphagnum peat moss does. if the plant is undersized and not watering entirety, you still must be certain you are watering all the way down to the bottom, or you are causing a larger proportion of superficial roots to grow near top.
so, if not watering entire pot, do make sure the area you do water is a solid column all the way down to the bottom of pot... not just wetting top haf or 2/3rds etc.
fertiize every irrigation in coco.. 1.3-1.5ec and well-balanced with a 10% runoff (waste water down drain or toss outside)... if you do this and the mix is proper, you will never run into concentration issues in substrate. observe and react to plant for fine-tuning, but it won't be far off.
if you do all of that, then yeah.. it's probably more to do with patience and perception than anythng else.. if deviating.. consider adjusting habits, then wait and see how it reacts. with coco / soilless just 1 irrigation without fertilizer makes a big difference in rate of growth.
The initial irrigaiton for sowing seeds does not need to have nutes in it, but after that it definitely improves rate of growth early on. a seed can power itself for 7-10 days but it can also make good use of a realtively mild concentrtaion of 1-1.5ish early on.. ramping up from a slightly lower point is fine too, but shoudln't be reuired.