Triplet error when deleting bars Dorico 4

I have a weird problem:
When I want to delete bars, suddenly Dorico is shifting two voices, although I have not activated the insert mode, AND additionally I tried to set this red safety barline, but it all didnt help:
Here I wanted to delete the bars 133-135

and aparently somehow because of the last big triplet, he is shifting the music in Oboe 2 and CorAnglais.

Any idea why, or whether I did something wrong? Or is it a strange rare bug?

just found out:
if I delete at first the music from these instruments

then it doesnt happen:

No need for the red stop line for this operation. When you see that, it means some form of Insert mode is active. To delete bars you should be able to just click the trash icon at the left of the system track selection.

no, absolutely no insert mode was active and I used exactly the trash Icon to delete the bars

Try updating to Dorico 4.0.20, released today, to see if this problem is resolved. If not, and you can reproduce it at will, please provide the project itself together with some steps to reproduce it, and we’ll be happy to take a closer look.