HLS data throght CCR1036-8G-2S+ sometime connection timeout

Hi.
I have CCR1036-8G-2S+. It use to transfer video in HLS format. On one 10G port connected server and clients to other 10G port. We have two subnets 172.17.17.0/24 for clients and 10.17.17.0/24 for server.
I create a bridge and added both ports. On bridge I created two ip addresses: 172.17.17.1 and 10.17.17.1. Server has ip address 10.17.17.2
All works, HLS send to clients. But sometimes (when client try to get video chank) rise tcp connection timeout on client side. When I disabled “Connection tracking” all works fine.
Why this happend?

And other question: After update RouterOS to version 7.1.3 I have something strange on menu IP-Routes (in web interface). Sometimes not work button “Add”, sometimes not showing added routes. List of routes can change after refresh page. Who has this bug?

p.s.
Sorry for my english…