Have the same issue on the latest version of Obsidian on Android. Even more general one: any header may have random style, not necessarily after a url link.
Unfortunately, I cannot stably reproduce it: the bug appears randomly for me and the header style sometimes fixes after reboot (and sometimes not!).
SmartSelect_20211024-185157_Obsidian|690x375
I have this bug on each version since mobile release.
P.S. I am not going to create a new issue since this one already exists.
P.S.S. From the screenshot one can see that I have a custom style for headers (colouring). The bug is not connected to that: I had such behaviour even before custom styling.