Non causality in metrics

[Alcu-ino]

Hello,
this is one of my first posts, so I apologize if I do something wrong.
I have an issue with the metrics recorded in the player.
I receive a stream in FFmpeg via RTMP, then it produces chunks for low-latency transmission and posts them to a server (-use_timeline 0 -use_template 1).
When I play the stream in the DASH reference player, I get non-causal data because "seconds behind live" is less than the "video buffer" (I can’t predict the future yet).
If I use -use_timeline 1, the data seems coherent with reality, but I think it is no longer a low-latency transmission.
I don’t understand why the player seems to lose the time reference when evaluating "seconds behind live," while the "video buffer" metric still makes sense to me.

Here is my FFmpeg script: https://pastebin.com/dMUP3Sv8
Here is an image of the non-causal playback:

Here the image of the riproducion with timeline flag on: