How he works is when he is "puffing" he is counting down until he becomes conversational again.
What I will do in an attempt to mitigate your issue is I'll leave him looping the puffing animation until you speak to him again, instead of being on a timer which is, as you say, likely interrupted by wielding the GLAIVE. Thus he should "puff" until you speak to him, no timer involved. It should allow him to flipflop without breaking anything. I haven't reproduced your actual bug, but I can sort of see why it would happen in any case.