How could this be? This code does exactly what it needs to do, if I remove the line then it stops working. And yet the editor complains about something

Should I simply ignore it?
ForAll(
Filter(
Tijdsloten,
'Team nummer' = TeamNr.Value && Datum >= dayStart && Datum < dayEnd
),
Patch(
ThisRecord,
{ 'Toegewezen offerte': LookUp(Offertes, Offerte = 'Toegewezen offerte'.Offerte) }
)
)