Hey @jkns! Thanks for reaching out. 
I've talked to our team here and they're definitely aware of this particular issue; it seems there is a race condition on initial page load that is causing selectedSourceRow to become unset.
It's hard to say when we'll be able to push out a fix, but there's a relatively straightforward workaround you can utilize, in the meantime. Try defining a success handler similar to the following on the query that is fetching your table's data.
The trick is to debounce it just enough to bypass whatever race condition is at play. I hope that helps! Let me know if you have any follow-up questions and I'll be sure to provide any additional updates here as soon as possible. 