The only solution is to use an html stripping site. This was the advice given to me by Marketo support, it was the only way he could find to fix the problem. If you paste your text into
www.striphtml.com and strip everything out, then cut and paste the results into your calendar file it works. You have to put all the line breaks back in and test it thoroughly though.
If you then make changes you have to be very careful to type everything new manually, otherwise it all starts up again and you have to go back to the strip html site.
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