Is it kind of normal experience? When I'm just on static, already downloaded page or default Tor browser page, in network statistics on PC every ~5-10-20 sec small unidentified packets send or receive some unclear data.
There are a few things that could affect traffic timing:
Tor itself sends padding cells randomly following the padding spec.
Obfs4 can delay traffic, but I don't believe it sends its own periodic cover traffic.
So my guess is that you're seeing Tor's padding traffic. If you disable Obfs4, you should still see this traffic.