Hi @Anonymous User,
What locale format is your ArcGIS account set to, and your device and browser? Do you use multi language surveys and set the locale in the XLSForm?
If you are in Brazil, assume you are using pt_BR locale? If so you use comma for decimal point, and point for thousand seperator. This may be the issue with web app that the locale formatting is not being applied correctly based on your ArcGIS user account settings or browser settings?
Regards,
Phil.