Serious problem with playing techniques defined in a previous version

Recently I have opened a previous version project, I have noticed that the playing techniques that were defined using svg files, were converted to pixeled images. They are shown correctly in the project, though (as scalable svg files, not pixeled). In addition, as the were defined as default to be used in other projects, I can’t use them because in the new version projects they are empty (no svg, no pixeled image). I enclose captures:

Is this a known problem?

This looks like the same thing reported in this thread.
Please confirm you’ve updated to 3.1.10 (your signature says you’re in 3.0).

I have the version installed.
In addition, in the new version (3.1.0), for newly created playing techniques, the svg files are also shown as rasterized in the editor. I enclose captures:

There have been some changes in the way imported graphics are handled in the most recent version. Do you still have access to the original SVG? If not, you should, if no other way, be able to retrieve it from within your Dorico project (change its file extension from .dorico to .zip, then have a look inside it, inside the supplementary_data folder).

I hope you will find that if you reimport your graphic to repair your existing playing technique definition in 3.1.10, it will work reliably from this point onwards.

I will do this, but I have quite a lot of playing techniques defined this way… I understand that there is no way to batch-update them, right? Thank you in any case for your help, Daniel.

Unfortunately not, no. I’m truly sorry for the inconvenience.

Don’t worry, there are much more positive things that compensate these kind of inconveniences.
Thank you again.