sif export fails when viewbox values separated by commas

Whenever I try to save a file in .sif format, it brings me to a page saying this:

Traceback (most recent call last):
  File "synfig_output.py", line 1344, in <module>
    e.affect(output=False)
  File "/usr/share/inkscape/extensions/inkex.py", line 283, in affect
    self.effect()
  File "synfig_output.py", line 1053, in effect
    SynfigPrep.effect(self)
  File "/usr/share/inkscape/extensions/synfig_prepare.py", line 483, in effect
    propagate_attribs(self.document.getroot())
  File "/usr/share/inkscape/extensions/synfig_prepare.py", line 382, in propagate_attribs
    vx, vy, vw, vh = [get_dimension(x) for x in node.get("viewBox").split()]
  File "/usr/share/inkscape/extensions/synfig_prepare.py", line 454, in get_dimension
    return float(s)
ValueError: invalid literal for float(): 0,0,1277,546

and then this: File /home/gaberielsomerville/inkscape_Assets/Gloobell.sif could not be saved.

What I want is a file "Gloobell.sif" saved into a folder called "synfig_assets.

The version of Inkscape I am using was pre-installed for my pixelbook go, which uses Google's distro of Ubuntu. (Ver. 0.92.4)

Chrome OS version: 87.0.4280.109 (Official Build)(64-bit)

I have 2 different versions of python currently installed: Python 2.7.16 and Ver 3.7.3 (In case that helps).

The file name is Gloobell.svg, which is a creature for a project I want to animate.

To reproduce:

1. Install and open Inkscape.
2. Import an SVG file
3. Go to file -> Save as -> and try to save as a SIF file.
4. The above was my result but may be different for others.