Autoexertion and Redblade Banner - Not providing infinite power

Testing with enduring cry and Redblade Banner shield equipped, with autoexertion I get no endurance charges on cast. When testing with manual cast (no link to autoexertion), I get endurance charges exactly as expected.

It's possible this could affect the Chieftain passive (Sione, Sun's Roar) which has the same "Warcries have infinite power" language as Redblade Banner, but I don't have a character available to test with right now.