Daniel Puckowski

This issue should be resolved via release ```4.3.0``` available on npm: https://www.npmjs.com/package/less/v/4.3.0 Thank you for the report. This Less: ```css [popover]:popover-open { opacity: 1; transform: scaleX(1); @starting-style { opacity: 0;...

Thank you for the issue report. I'll spend some time this weekend on this issue and I will try to come up with a fix PR.

I think I have a fix. Will work on adding more tests and try to get a PR submitted this weekend.

PR https://github.com/less/less.js/pull/4314 should resolve this issue, but it looks like we may be having new CI problems.

FYI figured out the new CI issue so PR [#4314](https://github.com/less/less.js/pull/4314) can be merged after review.

There seems to be an issue with the CodeSandbox. @nicky132 Could you take a look at permissions? 

You may be able to access the CodeSandbox, but others may not be able to. You likely have to make the sandbox public/shareable. Trying to access the sandbox yields the...

I can now access the CodeSandbox. I will look for problematic Less in the CodeSandbox project.

I identified some syntax that is problematic starting in Less version ```4.2.1``` (```4.2.0``` is okay): ``` @media screen and(max-width:1280px) { .form-process-table { width: 1200px; > div { width: 960px; }...

I put together a PR which should address the issue I identified from the CodeSandbox: https://github.com/less/less.js/pull/4332 There are ongoing CI issues, but the tests pass locally.