Multi wan system seems broken since upgrade

[PotatoCarl]

i
since updatin to 17.1 my opnsense appliance is not stable with my multi wan setup anymore. i het plenty of timeouts if both wans are on the same tier. This worked perfectly before. both uplinks are up and running but anything from the lan stops after a short time. when i disable the secondary gateway and reenable it works again for some time.
my primary wan is pppoe my second dhcp via a avm router.

i tried various setting changes at the gateways but they work only a limited time.
when i ping from the opnsense some sites are accessible like 8.8.8.8 but others are not like www.spiegel.de.

it seems to be connected with the secondary wan at em3.

any help please?