Excel custom functions show BUSY! but async function is not called

I have an Excel Add-in having custom functions and taskpane. My client created a workbook having multiple sheets using my custom functions approximately 3500+ function calls in current workbook. When a user opens this workbook, I need to recalculate sheet so that only my functions are recalculated. To achieve this task, I have performed following steps.

Loop on sheets in workbook.
Search each sheet for my formula using worksheet.findAllOrNullObject() function.

if search result is not NullObject, then call ranges.calculate(). Which should trigger function calls.

var sheets = context.workbook.worksheets;
sheets.load("items/name");
await context.sync();
for (var i = 0; i < sheets.items.length; i++) {
    var sheet = sheets.items[i];
    const foundRanges = sheet.findAllOrNullObject(FORMULA_DATA[formula], {
        completeMatch: false,
        matchCase: false
    });
    await context.sync();
    if (!foundRanges.isNullObject) 
        foundRanges.calculate();
        await context.sync();
    }
}

Problem I am facing that when I call recalculate function, all cells referring to these functions show BUSY! which means that my function have not resolved promise yet, but no function is actually called. I added break points at start of each function during debugging but no code stops there (I a change a single cell then breakpoint is hit). I enabled run-time logging and it has entries for each call begin but no end call entry.

Also one of the cell reference is passed to all functions and if I change its value, then all function calls are made properly and it shows result as desired and logfile contains entries for begin and end for all calls.

Solution

After thoroughly investigating the issue, I have come to conclusion that this client was using other Add-in which had same function names and it was saved in workbook. When I recalculated the sheet range areas, it was trying to call functions from those old Add-in which was uninstalled earlier. Therefore all cells were showing BUSY! and since code was not there in excel these promises were never resolved. Once I removed all taskpanes from workbook and re-opened it this problem does not appeared again.

To save Taskpanes info

    Office.addin.setStartupBehavior(Office.StartupBehavior.load);

To Remove Taskpanes information, use File => Info => Check for Issues => Inspect Document => Inspect.

After it displays results , Task pane Add-ins => Remove All.