Hi,
In my company, I have an RB1100AHx4 router on which I have set up l2tp/ipsec clients for the routers of the companies I manage which are also from Mikrotik.
After updating to v7.18 I noticed that some web pages on the servers I access via VPN are no longer loading correctly, especially those using older software. I have tried all versions from 7.18 to 7.19.1 on my router and they behave the same. The only solution I found was to lower the mtu in the l2tp clients from 1450, which is the default, to 1400 and it seems to work.
I submitted this issue to Mikrotik as ticket SUP-188725 on May 22, which has not yet been taken over by the support team.
Thanks,
Geo