Guys, I did deselect the Package Accelerator in the Fritz Box and can confirm: the issue of skipping titles is gone.
But: As a result, the general Speed has decreased substantially: from 55Mbit/s to 12Mbit/s. Any comment on this?
(For the record, where to find this option in the Fritz Box: in the lower left corner click “extend / erweitert”, then “content / Inhalt” then FritzBox Support in the lower left corner. Then scroll down, there are all the options you need: Deselect Hardware, Layer 2 and Package, Activate and don’t restart your Box, otherwise all is back on again.)