Siri dictation seems to be cutting off early a lot lately - any idea why?

I notice that Siri dictation seems to be cutting off mid-dictation early a lot lately.

The symptoms are that I keep talking but Siri stops adding words. It still shows it's "wave" but it's like it goes deaf. I have to touch done, or the text area, and then start Siri dictation again to continue.

It's not at a fixed amount of content or time either. Sometimes it's longer, sometime it's shorter.

I tried an experiment in the Notes app just before saying "one newline two newline three newline...." just to see how far I would get. The first time I got through 17, the 2nd time through 28.

It's becoming more and more irritating lately, because you never know what Siri dictation is going to stop.

This is with an iPhone 6 Plus, iOS 8.3 and my home network which is a 2 Gbps fiber optic. So it's not network connectivity.

Are other people experiencing this as well?

Thanks,

doug