Bitmap.compressToInternal() not working

[phileo]

I am trying to capture map rendering as a Bitmap using the following code snippet:

com.carto.ui.MapView.mapRenderer.captureRendering(object : RendererCaptureListener() {
            override fun onMapRendered(bitmap: com.carto.graphics.Bitmap) {
                super.onMapRendered(bitmap)
                val bitmapFile = File(context.applicationContext.filesDir, "bitmap.bmp")
                ByteArrayInputStream(bitmap.compressToPNG().data).copyToFile(bitmapFile)
            }

        }, true)

The above code snippet works and provides a PNG file.

However, if I replace compressToPNG() with compressToInternal(), then the above capture fails and the resulting file cannot be opened.

Any ideas as to why compressToInternal() is not working?