You probably do not want to hear this, because it is not a real solution, but the absolute fastest way to work around this, is to enter the info manually.
Open the watchtower online, and for every week concerned, click the correct Watchtower# an article# (not required), copy paste the themes and enter the songs in the required fields. This is less than 5 minutes work.
(https://u.pcloud.link/publink/show?code=XZCIlOXZYAAoRoOHvfy17072MYCLBB2F7LH7)
Sometimes it helps to import another language first, but that didn't do the trick this time. Probably something in the workbook (it wouldn't be the first time, but it would be a hassle to find out what is wrong). If it keeps happening in future workbooks, it may require developers' attention.