TypeError: Cannot read property '0' of undefined on csso version 4.2.0

[ep1kt3t0s]

Hi,

On Windows. csso-cli version 4.2.0

Am I missing something or is this an actual bug?

$ csso -i style.css -o style.min.css --debug
## parsing done in 27 ms

Compress block #1
[0.001s] init
[0.007s] clean
[0.013s] replace
[0.008s] prepare
[0.001s] mergeAtrule
[0.004s] initialMergeRuleset
[0.002s] disjoinRuleset
[0.005s] restructShorthand
C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\index.js:299
            throw e;
            ^

TypeError: Cannot read property '0' of undefined
    at getPropertyDescriptor (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\css-tree\lib\utils\names.js:63:24)
    at getPropertyFingerprint (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\csso\lib\restructure\6-restructBlock.js:72:20)
    at List.<anonymous> (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\csso\lib\restructure\6-restructBlock.js:217:27)
    at List.eachRight (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\css-tree\lib\common\List.js:181:12)
    at Object.processRule (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\csso\lib\restructure\6-restructBlock.js:215:18)
    at Object.enter (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\csso\lib\restructure\6-restructBlock.js:297:25)
    at Object.<anonymous> (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\css-tree\lib\walker\create.js:11:16)
    at walkNode (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\css-tree\lib\walker\create.js:165:34)
    at List.walkReducer (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\css-tree\lib\walker\create.js:189:61)
    at List.reduceRight (C:\Users\u\AppData\Roaming\nvm\v14.16.1\node_modules\csso-cli\node_modules\css-tree\lib\common\List.js:229:18)