Adobe Sign for Dynamics 365 not working in Sales Hub

When I am trying to add a document to the agreement, I get the following error:

TypeError: Cannot read property 'contentDocument' of null

    at AddNewAttachment (https://fabrictest.crm4.dynamics.com/%7b636679301210000758%7d/webresources/adobe_/Scripts/AgreementHelper.js:231:60)

    at e.executeFunction (https://fabrictest.crm4.dynamics.com/uclient/scripts/app.js?v=1.3.163-180712-011820:1644:50634)

    at e.execute (https://fabrictest.crm4.dynamics.com/uclient/scripts/app.js?v=1.3.163-180712-011820:1644:50442)

    at https://fabrictest.crm4.dynamics.com/uclient/scripts/app.js?v=1.3.163-180712-011820:1417:4460

    at Array.forEach (<anonymous>)

    at https://fabrictest.crm4.dynamics.com/uclient/scripts/app.js?v=1.3.163-180712-011820:1417:3956

    at r (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:62209)

    at t._settlePromiseFromHandler (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:35834)

    at t._settlePromiseAt (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:37160)

    at t._settlePromises (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:39023)

    at n._drainQueue (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:2097)

    at n._drainQueues (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:2158)

    at MutationObserver.drainQueues (https://fabrictest.crm4.dynamics.com/uclient/scripts/preload.js?v=1.3.163-180712-011820:43:855)

This is when I am trying to create an agreement and add a document within the sales hub. My presumption is that the script is not compatible with the Sales HUB UI changes.

Anyone else facing this problem?

Thanks,
Ben