Can't load Spines

Hi,

Loading my own spines with the playcanvas-spine library results in the spine’s alpha being wrong and prints out the following error:

launch.js:7866 TypeError: Cannot set property 'priority' of null
    at script.Spine.initialize (spine.js:19)
    at ScriptComponent._scriptMethod (playcanvas-stable.dbg.js:27160)
    at ScriptComponent._onInitialize (playcanvas-stable.dbg.js:27178)
    at ScriptComponentSystem._callComponentMethod (playcanvas-stable.dbg.js:27578)
    at ScriptComponentSystem._onInitialize (playcanvas-stable.dbg.js:27583)
    at Function._helper (playcanvas-stable.dbg.js:24276)
    at Function.initialize (playcanvas-stable.dbg.js:24279)
    at Application.start (playcanvas-stable.dbg.js:23700)
    at launch.js:7241
    at Application._preloadScripts (playcanvas-stable.dbg.js:23489)

And it looks like so:

image
The example spines work fine when tested in my own project but my own spines don’t work. I’ve double checked to export to the 3.6.52 just like the hero-mesh spine in the examples.