react-bootstrap: Tooltip positioning problem

I have two Button instances that both have Tooltips. The first one is positioned relatively, and works fine:

The 2nd one is consistently rendered off across all browsers, and I just upgraded from 0.26.4 to 0.28.1 and the issue persisted identically:

The funkiest thing is that this 2nd Button is position: absolute; right: 100px;, but if I switch it to position: absolute; left: 100px; the Tooltip appears in the correct position.

Any ideas as to what might be causing this?

Thanks for your great work with the lib!