content of text fields fields disappears, can't edit custom fields

Hi,

since Version 5.8.1 i'm observing two bugs:

1.) the content of WYSIWYG fields and some text fields fields disappear after publishing. The text from theses fields will not be displayed on the published cpt post. Existing posts, created prior to the Metabox update, still display the text on the published page but not in the backend custom field.

2.) in WordPress Backend under MetaBox > Custom Fields > the "chevron down icon" on the right side below actions is missing, so you can't edit existing custom fields (!) - i only have duplicate and delete icons on the right side - edit icon is gone.

Please assist for a quick solution.