This is a big red flag and as I suspected it is the issue (at least with this example) when you set a UBAQ to advanced BPM you are REQUIRED to have a BPM enabled in the Update method for it to work correctly.
As a rule of thumb test each individual UBAQ manually in BAQ Designer and make sure you can do the update there before moving it to a dashboard.
As you stated if I follow your steps outlines I do in fact get that error, but as soon as I fix the UBAQ to work properly the error goes away
https://uce5342cf718ffdbf8cb12fdfe19.previews.dropboxusercontent.com/p/orig/AAja1kFeA3N1l7uMvDZEhpfwwOjI3bKuluk3HY0-Jilutrx0kUlZa7WOH_YzSsrZhw4KuO9UEA-cepVo6qeygUZB2awbbDbH51DGldc0EVohJF_5I17LPNKuPE31Sn5AshB8dupc-8QN5u6XWgN_tyi8bpNqLlpucQlO_Mo-FjFY2GD5uCXkP4cqjHDh3QaxTY9lhYP5VUFlBWY84hNEy1c4bJKOFLd980Q7JBouTu4XyrzA_Xr97DGtvp78RQ0vcg0X43Q9qukpTU5c2w7F4xLQOhlNT3cBRbOTeeaGMx1baNlKG8j0lRvv7sXKef5UVKd2WC8C2Nns3eXdVbV_JpAfdPV2PZk8UIEKkdadVvAK6w/p.gif?fv_content=true&size_mode=5
Even if that is not the exact problem in your original issue, the issue is that your UBAQ is throwing an error (of some sort) on update. You need to verify those UBAQs in the BAQ Designer first to figure out what the problem is.
PS: I did create 2 BAQS and followed your setup exactly TEST1 and TEST2 I only updated the one in the gif but the same principle applies.