Google NLP Sentiment not always working

Google NLP of sentiment doesn’t always work and I can’t work out why. I have a table and in some cases the Sentiment will analyse it no problem and other times it won’t.

In seems to be that longer blocks of text break it, but not always. Likewise if I have a paragraph break it is more likely to ignore it. But not always! And sometimes short bits (one or two words) will get anlaysed even though it’s fewer than 20 words.

Any tips or suggestions as to why? It’s a bit of a black box so I can’t see what is going on (or not).