Hi,
Multiple placeholders should work with 5.5R2 version. Could you please try to apply the latest
hotfix for 5.5R2 version? There was some defect that could cause crashing of your page.
If the hotfix does not help, could you please export the template, which is used on the page with multiple placeholders and provide us with the link to download it?
Best regards,
Ivana Tomanickova