The number of modes does not match

Background

I have developed a plugin to import and export Local Variables.

So I tried to run the export on a Figma sheet that already had Local Variables set up, and got an unexpected error. See the example code below.

Problems

The format of the value obtained by variable.valuesByMode is { [modeId: string]: VariableValue }. For example, a value like { '522:0': {r: 1, g: 1, b: 1, a: 1}, '522:1': {r: 0, g: 0, b: 0, a: 1} }.

I wrote a process that changes this key to the mode name. For example, a value like { 'Light': {r: 1, g: 1, b: 1, a: 1}, 'Dark': {r: 0, g: 0, b: 0, a: 1} }. Light and Dark values were taken from collection.modes.

However, one variable returned an unknown third modeId. The program crashed because of a modeId that does not exist in collection.modes.

In other words, I have reached the inside an if statement in the following code.

Example Code

const collections = await figma.variables.getLocalVariableCollectionsAsync();
const collection = collections[0]; // Assume a collection exists.
const variableId = collection.variableIds[0]; // Assume a variable exists.
const variable = await figma.variables.getVariableByIdAsync(variableId) as Variable;
const modeLengthOfVariable = Object.keys(variable.valuesByMode).length;
const modeLengthOfCollection = Object.keys(collection.modes).length;

if (modeLengthOfVariable !== modeLengthOfCollection) {
  // Is it possible to reach here?
}

Is this a known defect? Any information on how to fix this problem?

This is additinal information:

We are not using the Enterprise plan. Nevertheless, variable.valuesByMode for a variable returns 5 results.

Do you have any information about this defect?