Unity Web player crashes every alternate refresh in Chrome

Hi there,
I have Unity web player in Chrome that works perfectly on first load. However if I refresh the page or reload having clicked away from the page then the player instantly crashes. If I refresh again, then it works. This alternating success/fail can be consistently recreated with each refresh. In the logs, a fail produces only the following: 170831 15:51:47 ------------------------------------------------------------
170831 15:51:47 Instance starting, version 5.3.7f1_c347874230fb, UNITY_WEB_ENABLE_AUTODOWNLOAD: 1, GetDisableAutoUpdates(): 0
170831 15:51:47 Datafile https://showhub.showplans.com/sites/myplan/unity/0000000t.v1498836404.unity3d
... while a success produces a whole lot more. I would be grateful for any help or guidance. Thanks, Tom