Hey, thanks for the detailed report with steps to repro. This is the same bug as in the thread @kbrouder linked to: Canvas SDK: <Link> click handlers leak across webview mounts — clicking a link opens N tabs after N canvas opens. It’s listener accumulation in the Canvas webview, so the number of tabs opened grows with the number of Canvas tab open and close cycles.
I’ve filed it internally and linked both threads. No ETA yet, but your workaround (using a plain URL as text instead of <Link>) works, and I’d stick with that for now. I’ll reply here once there’s an update on the fix.