I have often troubles Text formatting in AGOL and it has been for years.
Worst is with text popup in 3D scene. I have to try 3-4 times to create hyperlinks before it works (by work I mean that the hyperlink is saved when I close the configuration window by clicking Ok and that the hyperlink is there when I open the popup og configuration window). If I am lucky it has the wanted font type and size, it is a bit random. Alternatively I have to create the hyperlinks in Word and copy it. Super practical... When it eventually works, hyperlink get lost when I edit text in the configuration window and have to do it all again. When fighting trying to get the hyperlinks working I regularly have to delete them. Often I have problem to select and delete the text with hyperlink and have try several times.
Have troubles as well with "Custom attribute display" popup in Map Viewer Classic as well. I always have to struggles to have consistent font type and size throughout. Makes me crazy. Even if it looks right in the configuration window different parts of text appears with different font type and size in the popup window.
Have had troubles in Description text for AGOL content as well.
I am really fed up now, ESRI has to fix those issues.
