There's something definitely wrong there, then. Please let us know what OS you're on, just out of interest. In the meantime, I'd try one or all of these: Firstly, I would try going to the preferences and in the General category turn off tool tips, quit Illustrator then turn them on again and see if the problem persists. Secondly, if you're using the interface zooming feature, take that down to as small as possible and try to use the freeform gradients—that may then show the link (it's at least worth a shot and if it works please let us know). Ultimately, this is one of those rare occasions where I'd recommend you go to the CC desktop app, uninstall Illustrator and then reinstall. Hope that helps.
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