This issue, as well as other variants of it, has been reported here. It has to do with the locale you've selected, and certain menu items not translating properly. As Asier Sarasua reports:
Trying other languages, I noticed the issue appears in languages where the string "&Raster" is NOT translated exactly as "&Raster". The problem is in languages with other translations (R&aster, &Ráster, &Rasterra, &Rastra...).
Some users report that selecting "Settings > Options > Processing > Reset to Defaults" and restarting QGIS solves this problem. For some, however, this does not work.
You can also fix this in "Options > Processing" as follows:
- Find the menu items normally in your toolbar under the "Menus" section of this screen.
- Expand the given item, and double-click on the "Menu Path" field.
- Replace the listed menu path with the appropriate menu designation.
- Restart QGIS.
Here's the menu settings screen:
Not only can you use this to put your functions back into the correct menu, you can use it to create new menus or rearrange items to your liking. For example, I've here moved the Aspect tool from the Raster menu to a new "Custom" menu bar.
I use this function to keep frequently-used algorithms close at hand, and also to declutter menus of items I do not use, but it can be an effective solution to this problem if "reset to defaults" does not solve this for you.