Issues with volume envelope curves

I have the following problem.
For a multivision, I lowered the volume of the audio file at the points where I comment live using the volume envelopes. This happens at many points in the multivision.
However, if I later insert two more photos in a sequence, all the audio tracks are moved and the volume reduction is no longer correct. Can I somehow prevent this by locking the following levels?

greeting
kubalibre