MW 1.34, PF=5.0.1 (731d226, Dec. 28th)
Prior to 5.0 #autoedit parser function could update templates without issue. Since PF 5.0 (and including 5.0.1) the autoedit parser function is dropping dates from the template when used.
Example:
{{#autoedit:form=MyForm|query string=MyTemplate[MyProp1]=ABC| ... }}
turns:
{{MyTemplate|MyDate1=2020-01-05|MyProp1=XYZ}}
into:
{{MyTemplate|MyProp1=ABC}}