Taglist with mode string and customTags seems to be not working

[flyingbaba]

Formfield:

## saved but not loaded back for editing
tags:
        label: Tags
        type: taglist
        customTags: true
        mode: string
        separator: comma

## saved all, but visible only once from options
tags2:
        label: Tags
        type: taglist
        customTags: true
        mode: string
        separator: comma
        options:
            key1: value1
            key2: value2

Values are saved to database, custom values too. They are not displayed if record opened for update. Only if options are present they react as expected only without customTags.