what does mean "Illegal Frame Error"

Error Name: Illegal Frame Error
Occurrences: 1
First Occurrence: 2022-01-20
Last Occurrence: 2022-01-20
Devices:
   fēnix® 5 Plus: 17.30
App Versions: 1.21.1
Languages: spa

//globals

enum
{
  ...
  CV_TO_FLOAT,
  ..
}

function convV(convTYPE, value)
{
    if(value != null)
    {
        var str_place;
        if(convTYPE == CV_TO_FLOAT)
        {////////LINE OF ERROR
        ....