Within an <apex:outputPanel />, I was using a "rendered" formula within the tag:
<apex:outputPanel rendered="{!If(AND(myObject__c.relatedObject__r.theSuspectField__c = 'The Picklist Value',myObject__c.myField2 > 0), true,false)}">
Ater I saved the page (and although the page would save), I started to receive warnings that I needed to close my
<apex:outputPanel rendered="{!If(AND(myObject__c.relatedObject__r.theSuspectField__c = "The Picklist Value",myObject__c.myField2 > 0), true,false)}">
I replaced the double quotes with single ticks again, hit save, and bam - they were converted to doubles again.
What gives?
Eventually I figured out that if I changed the order in which my fields were listed, the record would save as expected - no double quotes:
<apex:outputPanel rendered="{!If(AND(myObject__c.myField2 > 0,myObject__c.relatedObject__r.theSuspectField__c = 'The Picklist Value'), true,false)}">
I'm assuming that this it has something to do with myObject__c.relatedObject__r.theSuspectField__c being a picklist field, located on a related record. Why it works in an alternate position in the formula, beats me, but is probably one of those strang quirks of Salesforce.
I'll update as I find out more.
Note: I was using the inline VF editor, but saw the same issue when I attempted to resolve the issue within the Force.com/Eclipse IDE.