CocRestart is required for 'format' action to work properly

[ocraft]

Invoking CocAction('format') results in following error:

2020-08-07T14:59:05.078 ERROR (pid:21408) [attach] - Notification error: format [] TypeError: Cannot read property 'fsPath' of null
    at AutoPep8Formatter.provideDocumentFormattingEdits ( \AppData\Local\coc\extensions\node_modules\coc-python\lib\index.js:123320:49)
    at AutoPep8Formatter.formatDocument ( \AppData\Local\coc\extensions\node_modules\coc-python\lib\index.js:123266:31)
    at PythonFormattingEditProvider.provideDocumentRangeFormattingEdits ( \AppData\Local\coc\extensions\node_modules\coc-python\lib\index.js:123201:55)
    at PythonFormattingEditProvider.provideDocumentFormattingEdits ( \AppData\Local\coc\extensions\node_modules\coc-python\lib\index.js:123181:21)
    at FormatManager.provideDocumentFormattingEdits ( \.vim\plugged\coc.nvim\build\index.js:55661:47)
    at Languages.provideDocumentFormattingEdits ( \.vim\plugged\coc.nvim\build\index.js:54609:41)
    at  \.vim\plugged\coc.nvim\build\index.js:54375:32
    at new Promise (<anonymous>)
    at Languages.descriptor.value ( \.vim\plugged\coc.nvim\build\index.js:54367:16)
    at Handler.documentFormatting ( \.vim\plugged\coc.nvim\build\index.js:72636:51)

After invoking CocRestart everything works properly.

[ocraft]

New info: after opening a new buffer problem occurs again.