Inconsistent error message ''Action not allowed (line 298, file "<functionName>")" - google-apps-script

Question

Context
Using g-suite, I have a google form that users submit information to a google sheet. Code aligned to the google sheet takes the submitted information and outputs a google doc/pdf. This final doc/pdf is created by copying a master doc template, merging/appending sections from other template docs, and finally search and replacing a number of text-merge fields in the final doc. The part of the code that is failing is a section that is responsible from merging/appending sections from other template docs as referenced in the sample code.
The code is run from a 'trigger'. The trigger is configured as:
Select event source : From spreadsheet
Select event type: on form submit
Issue
Without making any code changes, recently the code has stopped working when run from the trigger, error-ing out with the:
Action not allowed (line 298, file "")
The actual line of code at 298 is:
'TargetDocBody.appendParagraph(element);'
I can run the function in question successfully in the GAS script editor by selecting Run -> Run Function -> . The function does NOT run when configured as a trigger. Normally I would chalk this up to a permission issue, however even I, the script owner/writer, cannot get the function to run when I am the submitter of the form. It does run successfully as mentioned above within the GAS editor.
I've given full write permissions to all template dates, directories where the files are ultimately saved, write permission to the google form, write permission to the google sheets etc etc and I still can't seem to get around 'Action not allowed' when run from a trigger. I've logged the active and effective users on failures and successes and they're the same output both times.
[19-04-24 09:52:28:837 EDT] Active user : tim_monaco#company.com
[19-04-24 09:52:28:839 EDT] EffectiveUser : tim_monaco#company.com
function MergeSections(ServiceTypeDoc,TargetDocBody)
{
var ServiceTypeDocNumElements = ServiceTypeDoc.getNumChildren();
for(var x =0; x < ServiceTypeDocNumElements; ++x)
{
var element = ServiceTypeDoc.getChild(x).copy();
var type = element.getType();
if(type == DocumentApp.ElementType.PARAGRAPH) //this is the problem line
TargetDocBody.appendParagraph(element);
if(type == DocumentApp.ElementType.LIST_ITEM)
TargetDocBody.appendListItem(element);
if(type == DocumentApp.ElementType.FOOTER_SECTION)
TargetDocBody.appendFooterSection(element);
}
}
Function should/has run without issues in the past. With no code changes, I would expect the same.
Actual results are a failure and stop mid execution with
Action not allowed (line 298, file "")
The actual line of code at 298 is:
'TargetDocBody.appendParagraph(element);'

Answer 1

This could be a situation where the error message is inaccurate. It often happens that quota limit errors don't happen initially, and then mysteriously kick in. Also, because it happens inconsistently, that would also point to a quota limit error. This could be a situation where your for loop is calling a service too often in a short period of time, and hitting a quota limit. I could be wrong, but I'd try putting in a try / catch and if there is an error, sleep the code and try again.
If the following code that sleeps when there is an error, doesn't work at all, then I'd consider that it might be a bug, and submit an issue.
function MergeSections(ServiceTypeDoc,TargetDocBody)
{
var ServiceTypeDocNumElements = ServiceTypeDoc.getNumChildren();
for(var x =0; x < ServiceTypeDocNumElements; ++x)
{
var element = ServiceTypeDoc.getChild(x).copy();
var type = element.getType();
for (var i2 = 0;i2<3;i2++) {//Try 3 times
try{
switch(true) {
case type == DocumentApp.ElementType.PARAGRAPH:
TargetDocBody.appendParagraph(element);
break;
case type == DocumentApp.ElementType.LIST_ITEM:
TargetDocBody.appendListItem(element);
break;
case type == DocumentApp.ElementType.FOOTER_SECTION:
TargetDocBody.appendFooterSection(element);
break;
}
break;//If there is no error then break the loop
}catch(e) {
Utilities.sleep(1500);//Wait x number of seconds
}
}
}
}