This has been reported a few times over the years.&nbsp; The 2016 reference sounds like it was resolved, but then reappeared in 2019.&nbsp; That thread didn't seem to conclude. From 2019: <a href="https://app.roll20.net/forum/post/7266026/" rel="nofollow">https://app.roll20.net/forum/post/7266026/</a> From 2016:&nbsp; <a href="https://app.roll20.net/forum/post/3124784/" rel="nofollow">https://app.roll20.net/forum/post/3124784/</a> I encountered this again last month, but haven't seen a response yet:&nbsp; <a href="https://app.roll20.net/forum/post/8514781/" rel="nofollow">https://app.roll20.net/forum/post/8514781/</a> So I'm reporting again in hopes of someone else encountering this.&nbsp; Here is a very basic example that anyone can enter into a custom sheet sandbox: &lt; input &nbsp; type =" number "&nbsp; name =" attr_stat "&nbsp; value =" 0 "&nbsp;/&gt; &lt; script &nbsp; type =" text/worker "&gt; &nbsp;&nbsp;on('sheet:opened',&nbsp;()&nbsp;=&gt;&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;setAttrs({'stat':&nbsp;1}) &nbsp;&nbsp;&nbsp;&nbsp;}); &nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;on('change:stat',&nbsp;(eventInfo)&nbsp;=&gt;&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;console.log(eventInfo); &nbsp;&nbsp;&nbsp;&nbsp;}); &lt;/ script &gt; When you open the sheet, you can see the stat is properly set to 1 (from a default value of zero, or whatever was saved in the input value).&nbsp; When you change the number field, you can see the console log fires with the eventInfo.&nbsp; However, that console log never appears when the sheet is opened and the value is changed to1 with the setAttrs inside a sheet:opened event.&nbsp; Though the stat value is changed, it doesn't seem to fire a change event. I was hoping to use a method similar to this to init a bunch of stats when a sheet is opened (which it does), but any listeners to those stats changing don't pick it up (like skill calcs dependent on the value of the stat).