Writing numbers in the format: ###-#### causes Safari on iOS to treat them as a phone link. This format would typically be used for year ranges, e.g. 612-1200.
Apple has an article about this here: https://developer.apple.com/library/archive/featuredarticles/iPhoneURLScheme_Reference/PhoneLinks/PhoneLinks.html
Possible solutions might be to hack around it with JS (if possible?), or perhaps disabling default parsing with <meta name = "format-detection" content = "telephone=no">, and require explicitly defining when something should be parsed as a telephone number using <a href="tel:1-408-555-5555">1-408-555-5555</a>.