I think most of us have read FAQman's guide and other stuff he wrote on the site, which includes the current version of the FAQ, the glossary and other guides. I think you also read how sentience needs at least ~25 hours to be achieved and a lot of personality work done during this time. You have probably seen some movements from your tulpa before this hour mark, but figured it was only you puppeting the tulpa. After all, it must have been you - the tulpa didn't move much after that and if it was really sentient, then it would be moving a lot. So, certainly it can't be a sign of sentience. You might have even heard a voice in your head that didn't seem to be yours, but there is no reason to think it's the tulpa's voice because you have no sign of sentience yet. So how could it possibly be able to communicate with you at this point?
But you have to wonder: why are there others that achieved sentience much faster than you did? Didn't FAQman say it can't be done before ~25 hours of work on your tulpa? So then how can there be so many people that achieved it before that time?
In all likelihood, your tulpa was sentient much sooner than you realised and certainly sooner that the ~25 hour mark. It probably tried to show you that it is sentient by moving few times (or sometimes only once), but after a short while of giving you signs of sentience it stopped trying. Possibly because it feared doubt on the creator's end - most creators see fast progress and become paranoid that they're puppeting or parroting. So it probably stopped giving you signs, except maybe small ones that you ignored like the occasional wiggle to see if you still fear puppeting.
This of course makes it harder for some to realise thier tulpa is actually sentient. Most tulpæ will continue trying make you aware of their sentience, will wait until you reach the hour mark and not do anything until then or will get "fed up" with your actions and will try to confront you.
Either way, this can easily result in a annoyed tulpa just because you don't believe it. If you don't stop thinking that your tulpa can't have a certain trait or characteristic before certain hour mark is met, it can slow down the progress you'd otherwise attain in creation, or build trust issues. It's entirely possible that by the time you do recognize sentience, your tulpa may be holding a grudge.
This is one of the main things that slows down sentience and also other traits. One of the biggest things that hurt the creation process is believing your tulpa wasn't responsible for something it did. This is an issue because when the tulpa tries to prove you aren't puppeting it - that it's moving by itself - you assume it isn't done by it. But it can be found separately, e.g. when you don't believe that a tulpa has done something, because you aren't sure you haven't done it.
The problem in that case is that you either knowingly puppet your tulpa, the tulpa is moving by itself, or it's an intrusive thought. But even if it was an intrusive thought it won't hurt the tulpa, so you shouldn't be worrying so much about this.