Ok, I see your concern now. As a general rule, player skill is modeled as a Gaussian, and SR values below 0 are extremely near that value. There isn't -27.04, more like -0.02. Think of it as a value that is slightly aggressively rounded.
As a sidenote, the previous old versions (the ones that didn't crash) had some issue with the old vanilla client that might cause some value to be surprisingly set to 0, so some fixes have been added to avoid some weird edge cases. That issue need monitoring to check if the fixes completely solve the issue in the new version, or if more additional work is needed.