White screen of gobbledygook

Hello, very strange issue arose since yesterday. We’re running the latest version of the plugin 0.9.5.4 and what’s happening is on some pages it’s displaying this: https://greatdigitalsolutions.co.uk/clients/errors/screengrab.png

And then a simple refresh of the page thereafter loads it as per normal. Having done some Googling and reading up on forums I’m lead to believe it could be memory-related or something to do with W3 Total Cache, so I’ve deactivated the plugin and the problems appears to have gone away.

Has anybody encountered this issue before?