When you run a Best Practice check on forms and reports, it will check labels that end with a punctuation. These are in general not allowed, except in help texts.
There is in SysBPCheck.checkLabelBasics a list of approved exceptions to the rule. This list however, is in EN-US only. If you run BP in EN-US the label “Invoiceno.” is all right, but if you run it in for example Danish, the Danish equivalent to this label, “Fakturanum.” will give you a BP error.
So if you run a BP check in any language apart from EN-US you could end up with a lot of BP errors from SYS elements.