Hi, yes there is/was also one in Mallorca. Nice to see a more complete label and of course it moves the example on Ysartglass.com to Barcelona as well as giving a better dating to suit Ivoś original thoughts there... another one to update.
Note also that Isart with an I is also the original spelling for the unlikely to be related Ysart family. Having a signature on your piece also helps to indicate that Isart was a retailer there.