Windows 10 Mobile keyboard won't suggest big words

[roryok]

I recently bought a second hand Lumia 950 to make the leap to WM10 after years of using and loving WP8.1. However, I'm not enjoying the experience, mainly due to the keyboard which seems inferior for one key reason - it doesn't like big words.

Here's a selection of 10 random big words I tried typing into both the L930 and L950

WP8.1/930 - WM10/950
Authenticity - Airtricity (electricity company pulled from phone contacts)
Fabrication - Fabrication
Logistical - Logical
Transgression - Tension
Gargantuan - German
Lilliputian - Lookin
Aristocracy - Stacey
Pulchritude - Office (!)
Semolina - Sermons
Portfolio - Portfolio

WP8.1 scored 10/10. WM10 scored just 2/10. Granted it's not every day that you use the words lilliputian or pulchritude in a sentence, but the point is Wp8.1 had no problem identifying and suggesting even rare words like these, where WM10 couldnt even identify authenticity

Why doesn't WM10 suggest the correct words? They're definitely in the dictionary, if you tap them out it suggests them eventually, but it seems to have over-zealous error correcting on swipe mode.

It's a long shot, but is there any way to fix this? I love the UI improvements that WM10 has made over WP8.1 and I'll miss them if I have to revert, but this keyboard is driving me crazy.