Hi Stella,
This issue looks to be specific to using the shrink to page width option. We do have a bug logged for a similar situation (352294), but only have two customers have reported it to Microsoft as a problem. There appear to be a few different workarounds including using the web viewer or Excel to view the report, possibly adjust the font styles being used, or adjust the shrink to page options.
If you do feel strongly about getting this fixed send me a message by clicking on my name and let me know a bit more information. I can't promise that we'll fix it, but I'd be happy to better understand the scenario that makes this important for you.
Thanks
Ryan
