iMessage 'delivered' status discrepancy between iPhone and iPad

My imessage text is missing “delivered” tag below my latest text. It says “delivered” under my previous message but I know the recipient didn’t block me because they have sent me a text after my message but not an answer to my question just an unrelated text. This happened to me before with the same person and i’m having trouble understanding if they got my text or not. When i check on my ipad it does say “delivered” but my iphone doesnt say anything about whether it was delivered or not. Is this a glitch or did they actually not see my message?