Hi, 
Since yesterday, some questions and question groups are not displayed anymore in my survey: when I want to visualize these questions or question groups it is not possible anymore. Yesterday I did different modifications in these groups (hiding some questions in the group but not all, changing the text of some questions etc.), but nothing different from what I have done many times before without any problem. 
For some groups of questions, I solved the problem by setting different group conditions, then going back to the original conditions and it worked (no idea why). For other groups it does not work (I tried changing conditions or getting rid of them altogether) even for groups where I never had conditions. I set up a variable through a hidden equation at the beginning of my survey and I condition on different values of this variable. 

Has anybody had that problem and do you know how to resolve it?
 I am worried if that happens regularly as I am launching the survey with a survey company next week, and I should be testing the survey today.  

Your LimeSurvey version:  Version 5.4.9
Own server or LimeSurvey hosting: Limesurvey hosting
Survey theme/template: Fruity
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(Write here your question/remark)

Each time you update sometging and seems there are an issue : remind to check the Survey Logic file

Thank you very much I will check this out!