Oh, but I think I know where the issue comes from. I am using this form for posibility of editing item which could be open from different galleries.
Each gallery is based on Status of issue... "Returned to Requestor", "New"...
S I had to use variable to distinguish from which Gallery I came from and where to go back. So there is the following condition on Item:
If(var1galleryitemselected=true, Gallery1.Selected,
var11galleryitemselected=true,Gallery1_1.Selected,
var12galleryitemselected=true,Gallery1_2.Selected,
var13galleryitemselected=true,Gallery1_3.Selected,
var14galleryitemselected=true,Gallery1_4.Selected,
var15galleryitemselected=true,Gallery1_5.Selected,
var16galleryitemselected=true,Gallery1_6.Selected,
var17galleryitemselected=true,Gallery1_7.Selected,
var18galleryitemselected=true,Gallery1_8.Selected,
vargalleryrequestorraisedissue=true,GalleryRaisedIssuesRequestor.Selected)
I tried to use only If(vargalleryrequestorraisedissue=true,GalleryRaisedIssuesRequestor.Selected) - save changes and it works...