nope! Nothing wrong here in the raw data of OpenStreetMap. The problem is "ORM", please report an issue to the developers there.

This is how it is currently tagged.
The proposed electrification is correctly "inactive" tagged with the lifecycle prefix "proposed".

electrified	no
gauge	1435
maxspeed	100
name	Voreifelbahn
operator	DB Netz AG
passenger_lines	1
proposed:electrified	contact_line
proposed:frequency	16.7
proposed:voltage	15000
railway	rail
railway:etcs	no
railway:lzb	no
railway:preferred_direction	forward
railway:pzb	yes
railway:radio	gsm-r
railway:traffic_mode	mixed
ref	2645
source	BingSat;knowledge
tracks	1
usage	main
wikidata	Q1699351
wikipedia	de:Voreifelbahn