Recv video delay when sender's outbound packets lost

mediasoup libraries
1

Issue description
1 webapp A, B and C are in the conference room. Using clumsy to drop outbound packets with 12% lost rate on webapp A’s host.
2 Both webapp B and C see A’s video have same 2 or 3 seconds delay sometimes. (sometimes recv video delay is low)

Question:
1 Where the delayed packets are buffered, mediasoup or webapp B and C?
2 How to reduce the recv video delay by modify mediasoup’s code or config?

Thanks.