Sword of Rahyeh, the node on the last column of Paladin’s tree states that it gives additional ignite chance “if you have cast a spell recently” (doesn’t mention needing to be cast directly). Despite that, if you proc Holy Symbol, which states “when you block you cast Holy Symbol” (which has a spell tag), it doesn’t cause Sword of Rahyeh to give the ignite chance, atleast according to the tooltip. I’m also fairly certain it is not a tooltip error, since manually casting a spell causes the tooltip dps to reflect the buff.
Looks like Sword of Rahyeh is set up to work only with direct casts. I will double check to make sure this is intentional and if it is, we will update the tooltip to match this functionality.
Thanks for the report.