Hello Yvonne,
It true that it is strange !
What is your OS, your Archicad version, your hardware ?
Where do you see this kind of mistake ? (into a special view, all views)
What are your view parameters ?
Did you try to change your dimension parameters ?
Christophe - FRANCEArchicad Designer and Teacher
Archicad 15 to 27 FRA FULL
OS 11.6 Big Sur - MacBook Pro 2017 - 16Go RAM
"Quality is never an accident ; it's always the result of an intelligent effort" John Ruskin