I've run into this crash many times now. Today, I created a quick house floor plan visualization for a friend. Fairly small project. I added a few generic models to fill out the space. There are some C4D native materials mixed in as well. In this scene, I moved the group of objects to the top to make things easier to find (called These Materials). I wanted to delete all the material tags (Corona materials) and just apply one simple material to the parent null using Cubic. I selected all the tags, hit delete and crash. Every time I tried it crashed. I then tried deleting one tag, no problem. I deleted five tags. No problem. I also tried 10 without issue. When I deteted 15 tags, it crashed. I don't think this is a major issue, but shouldn't be happening nonetheless.
This happened with the December and the new January Daily Builds. I have not tried it in v6 stable release. I also have not tried these sequence with a plain C4D scene with no Corona elements.
I will now upload the project file and bug report to the private uploader. The regular uploader either didn't work or was too slow and timed out, at least the Captcha was timing out. I used the Dropbox method. The file is called "Alex Campuzano_Corona 7 Crash" 140MB.