?

Not at all. Man's been whipped for Mo forever

In the very beginning of the series, he tian actually did have feelings for Jian yi, however once he met little mo he longer pursued jian yi cause he started liking mo

It's more or less true; he was originally introduced as a "potential love rival" to XiXi, more or less-- but Old Xian scrapped that plotline very early on, immediately after having him and Mo meet. We never got a confirmation from He Tian himself that he liked Jian Yi in the short period where it was supposed to be a thing, tho, so it's not necessarily canon. You could argue that he stopped pursuing Jian Yi after falling for Mo, or that he has always been in love with Mo only; the narrative itself isn't contradictory to either assumptions.

As someone who has been reading this since the very beginning, the period where He was infatuated with Jian Yi (from a meta POV) felt a bit longer than it probably was, so I personally am all for believing He Tian did like him for a while-- buuut, again, no official confirmations or denials on the matter.

Not sure whether Old Xian has ever commented on the subject too