I can confirm this is still reproducible. Also, it seems that with ETP set to Standard, the page loads the elements slower compared to Chrome.
Bug 1688890 Comment 2 Edit History
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I can confirm this is still reproducible. Also, it seems that with ETP set to Standard, the page loads the elements slower compared to Chrome. Tested with: Browser / Version: Firefox Nightly 210217 (🦎87.0a1-20210217094559🦎) Operating System: OnePlus 6 (Android 10) - 2280 ×1080 pixels, 19:9 ratio (~402 ppi density)