Drop-down menu missing blog item page

[NandoPiz]

HI, I have an issue with taxonomies tag.
The problem is that when I create a new blog item page under Taxonomies I found the right Category (blog) but some tags are missing form drop-down menu. I mean that totally I have 6 tags defined but when I create a new blog item page on 4 are showed in the drop-down menu
If I create a new tag and add it apparently works BUT this is missing again in the drop-down menu on the next blog item creation.
Any ideas?
Grav version 1.7.9
Taxonomi List plugin 1.3.5
Theme: Quark Open Publishing 2.2.7