texlab root not being detected correctly

[a-torgovitsky]

Description

Directory structure is this:

tree ./texlab-root-mwe  -a --dirsfirst -L 2                                                        ─╯
./texlab-root-mwe
├── ch1
│   ├── ch1.aux
│   ├── ch1.fdb_latexmk
│   ├── ch1.fls
│   ├── ch1.log
│   ├── ch1.pdf
│   ├── ch1.synctex.gz
│   ├── ch1.tex
│   ├── .texlabroot
│   └── texlabroot
├── .git
│   ├── branches
│   ├── hooks
│   ├── info
│   ├── objects
│   ├── refs
│   ├── config
│   ├── description
│   └── HEAD
├── main.aux
├── main.fdb_latexmk
├── main.fls
├── main.log
├── main.pdf
├── main.synctex.gz
└── main.tex

7 directories, 19 files

If I open ch1.tex then :LspInfo shows that the root directory is the top level ./texlab-root-mwe. My understanding is that the presence of either .texlabroot or texlabroot (I have both) should force the root directory to be detected as ./texlab-root-mwe/ch1. This issue was discussed in texlab, but the conclusion was that it was the domain of nvim-lspconfig. #3005 seems aimed at addressing the same issue, but doesn't seem to have worked?