Similar: InDesign 2020 15.1.3 on iMac 10.13.6:
A paragraph has a style, and two character styles are used in it. I select some text with one of the character styles, apply an existing hyperlink (URL) to the text. The style of the text reverts to paragraph style. So, if I reimpose the character style, then ID doesn't indicate a link exists. That particular link is missing in the exported PDF, but if I check the text in ID it appears as 'editing' the hyperlink and shows the URL is applied.
Similar: InDesign 2020 15.1.3 on iMac 10.13.6:
A paragraph has a style, and two character styles are used in it. I select some text with one of the character styles, apply an existing hyperlink (URL) to the text. The style of the text reverts to paragraph style. So, if I reimpose the character style, then ID doesn't indicate a link exists. That particular link is missing in the exported PDF, but if I check the text in ID it appears as 'editing' the hyperlink and shows the URL is applied.