iOS 11.3 iMessages saying delivered but not always actually sending

Hi guys,I have a iPhone 6 running ios 11.3 when I message someone via Imessage no matter what iOS version the other person is on. Lots of the time for example if they text me and I reply it says the imessage was delivered but the other person never got the iMessage and then 10mins later they message again saying did you get my message then when I message them the second time it works. i watched a YouTube video about this glitch but that was way back from iOS 8 but 2 other people have commented on the video saying they have this same issue on iOS 11.3. Should I turn off iMessage untill Apple release a fix for this most likely on iOS 11.3.1? As I do not think this issue can be waited out until iOS 11.4 as this is a major issue where it is saying the iMessage is delivered and the other person never gets the message.

Many Thanks