Accents are often not shown on caps historically due to limitations in the size of characters. Same thing everywhere in Belgium I think https://www.mapillary.com/app/?focus=photo&lat=50.602373588037&lng=4.9006459091002&z=17.311815371902032&pKey=290411462726768

The document at fgov.be doesn't seem to contain any diacritic anywhere (see e.g. the words "general", "Releve") so this is more of an encoding issue.

Étalle is correct