Hey there!
In the situation shown in the “before” image—beamed quavers—, when I try to tie the two first f notes together, Dorico splits the four beamed quavers into groups of [2]–[2], as shown in the “just after” image. What is actually going on there?
The time signature is ¾, with no change in the whole flow.
Thanks!
Albert.
I couldn’t reproduce this with the default settings… did you at some point prior to the tie operation change the Notation Options>Beam Grouping (Beaming eight note together in quarter note denominator time signatures) … anyways, this setting should restore your beaming 
Oh, ok… that’s fine! It was enabled a Note Beaming parameter in Notation Options that would cause to break these beams… thanks, fratveno!!!