wierd condensing

I write a short piece for orchestra, with 4 1stV, 4 2ndV, 6 Alti, 4 Celli and 4 ContraB.
I used condensing to reassemble the score with 2 V1, 2 V2, 3 A, 2 Vc and 2 CB.
At the beginning, when I switched “condensing” noting happened except the two lines of A3 which were only condensed.
Searching for a reason, I remarked that, on every set of two adjacent players (i.e. V1-1a & V1-1b, or Vc1a & Vc1b) the first one had a “+” on its player’s label, and not the second one. More of it, the only players that could be condensed (the A3) had no “+” on their label.
So I started a boring work, copying the text of all the “+” instruments into a line without “+”.
At the end, it worked perfectly. The 22 staves in the original could exactly condense in 11 staves.
BUT, when doing this, the time, which I intentionally placed on the top of the score, reappeared in the middle, only once (i.e. it stays, normally, on the top…… and appears in the middle after the 5th staff). And the brackets grouping the staves (V1, V2 etc…) disappeared, only a one-line bracket remaining on the very staff where the time reappears!
All those bugs are really boring and I couldn’t find an explanation in the operation manual.
For example, why is an instrument always included with “+” when you put it in your score? It has to do with players who play more than one instrument, but why isn’t it a choice to do?
Thank you for your help.

More precisely : the Time signature appear on top of the score and before the V2 group. When condensing, it appears on top of the score and before the group of A3.

Are these section players? Solo players? Are you using individual players for each of these, or one player with divisi? Have you told Dorico to condense section players, if you’re using section players?

There may well be bugs here, but equally it could be that you’ve set up the project in a way that’s not conducive to Condensing. Please upload a cut-down version of the project that demonstrates the problem.