About VS Code:
Version: 1.38.1 (user setup)
Commit: b37e54c98e1a74ba89e03073e5a3761284e3ffb0
Date: 2019-09-11T13:35:15.005Z
Electron: 4.2.10
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Windows_NT x64 10.0.17763
Remote info:
Distributor ID: Ubuntu
Description: Ubuntu 18.04.3 LTS
Release: 18.04
Codename: bionic
Steps to Reproduce:
Does this issue occur when you try this locally?: Does not happen when using not-WSL projects
Does this issue occur when you try this locally and all extensions are disabled?: Yes/No N/A??
Let me know if you need any other info.

For what it's worth, I've tried uninstalling the Angular Language Service on WSL and reinstalling it with no luck. I only tried this because, for some reason, the Docker extension icon is visible and was the only one I installed since this issue started.
Some icons appear at random, but are missing again after restarting the app. If I notice a pattern I will comment here, but so far it seems completely random.
Hello, I'm experiencing this issue as well.
About VS Code:
Version: 1.39.0-insider (system setup)
Commit: b0d714d2de2886060e0904bf0cc774e0d70667cd
Date: 2019-09-26T09:07:24.281Z
Electron: 6.0.9
Chrome: 76.0.3809.146
Node.js: 12.4.0
V8: 7.6.303.31-electron.0
OS: Windows_NT x64 10.0.18990
uname -rv:
kernel: 4.19.67-microsoft-standard
For me, sometimes the icons appear if you hover over the bar:

I noticed something strange in the webdev console.
Failed to load resource: net::ERR_INVALID_URL
vscode-remote-resource?path=%2Fhome%2Fcassini%2F.vscode-server-insiders%2Fbin%2Fb0d714d2de2886060e0904bf0cc774e0d70667cd%2Fextensions%2Fgit%2Fresources%2Ficons%2Fdark%2Frefresh.svg&tkn=b17cd3a4-53a6-4dc8-9d73-13285efe8bfd:1 Failed to load resource: net::ERR_INVALID_URL
vscode-remote-resource?path=%2Fhome%2Fcassini%2F.vscode-server-insiders%2Fextensions%2Fmhutchie.git-graph-1.16.0%2Fresources%2Fcmd-icon-dark.svg&tkn=b17cd3a4-53a6-4dc8-9d73-13285efe8bfd:1 Failed to load resource: net::ERR_INVALID_URL
vscode-remote-resource?path=%2Fhome%2Fcassini%2F.vscode-server-insiders%2Fbin%2Fb0d714d2de2886060e0904bf0cc774e0d70667cd%2Fextensions%2Fgit%2Fresources%2Ficons%2Fdark%2Fopen-file.svg&tkn=b17cd3a4-53a6-4dc8-9d73-13285efe8bfd:1 Failed to load resource: net::ERR_INVALID_URL
vscode-remote-resource?path=%2Fhome%2Fcassini%2F.vscode-server-insiders%2Fbin%2Fb0d714d2de2886060e0904bf0cc774e0d70667cd%2Fextensions%2Fgit%2Fresources%2Ficons%2Fdark%2Fclean.svg&tkn=b17cd3a4-53a6-4dc8-9d73-13285efe8bfd:1 Failed to load resource: net::ERR_INVALID_URL
vscode-remote-resource?path=%2Fhome%2Fcassini%2F.vscode-server-insiders%2Fbin%2Fb0d714d2de2886060e0904bf0cc774e0d70667cd%2Fextensions%2Fgit%2Fresources%2Ficons%2Fdark%2Fstage.svg&tkn=b17cd3a4-53a6-4dc8-9d73-13285efe8bfd:1 Failed to load resource: net::ERR_INVALID_URL
vscode-remote-resource?path=%2Fhome%2Fcassini%2F.vscode-server-insiders%2Fextensions%2Feamodio.gitlens-10.0.1%2Fimages%2Fdark%2Ficon-stash-save.svg&tkn=b17cd3a4-53a6-4dc8-9d73-13285efe8bfd:1 Failed to load resource: net::ERR_INVALID_URL
It seems like the icons are trying to load, but they have an invalid URL.
@Kai-Richardson Insiders was broken for a couple days and was fixed via #1502
@ShiftyMcCool Could you please try out Insiders?
Confirmed fixed on my machine.
Version: 1.39.0-insider (system setup)
Commit: 313ede61cbad8f9dc748907b3384e059ddddb79a
Date: 2019-10-01T07:29:05.652Z
@alexandrudima After installing Insiders I noticed the same issues. However, I was thinking about the "random" nature of this issue and decided to try a few things to narrow it down. Long story short, I found that it's an issue with being behind my corporate proxy. The "random" times that they were working was when I was coding from home outside the proxy or at the office on the open wi-fi.
So far, I can't seem to get around this. I added the proxy to VS Code settings but it has no effect. I also set the http_proxy env variable in WSL to my corporate server with no luck.
At this point you can probably consider this closed since the issue is on my end.
Thanks!
@ShiftyMcCool ahaa! Thanks very much for following through... I am not 100% sure if we should attempt to repro and it might improve with the recent changes from @aeschli where the resolver now returns [::1] and not the ip address of WSL...
So I would close this issue for now, and keep our eyes open in case other issues pop up, and then immediately ask them about proxies... If it turns out to be a common problem, we can then further investigate.
Most helpful comment
@alexandrudima After installing Insiders I noticed the same issues. However, I was thinking about the "random" nature of this issue and decided to try a few things to narrow it down. Long story short, I found that it's an issue with being behind my corporate proxy. The "random" times that they were working was when I was coding from home outside the proxy or at the office on the open wi-fi.
So far, I can't seem to get around this. I added the proxy to VS Code settings but it has no effect. I also set the http_proxy env variable in WSL to my corporate server with no luck.
At this point you can probably consider this closed since the issue is on my end.
Thanks!