I can't reproduce but it looks like it would be reproducible.

Maybe related to 807604. sfiera, is the local NTP on at some % of Beta?

Yes, the local NTP is on 50% of Beta. It looks like we were trying to load an interactive Doodle there. That's supposed to be disabled, maybe something's wrong with the configs. I'll take a look.

I can't find anything wrong with the Finch configs. tldr@fernandomiguel.net, did you change any flags on chrome://flags? In particular, manually enabling chrome://flags/#doodles-on-local-ntp would have this effect.

re #2, this is not quite  bug 807604 , it fails even earlier :)  The problem is that /ddljson (the Doodles API) returns an iframe URL with a country TLD. It should return either a relative URL or an absolute URL pointing to google.com. So the bug is on the server side, but we (Chrome) should still handle this better. I've filed  bug 813513  for that.

indeed chrome://flags/#doodles-on-local-ntp is enabled

Command Line	/Applications/Google Chrome.app/Contents/MacOS/Google Chrome --flag-switches-begin --autoplay-policy=document-user-activation-required --enable-device-discovery-notifications --enable-audio-focus --enable-offer-upload-credit-cards --enable-devtools-experiments --enable-embedded-extension-options --enable-fast-unload --enable-fullscreen-tab-detaching --enable-google-branded-context-menu --history-entry-requires-user-gesture --enable-hosted-app-quit-notification --enabled-new-style-notification --enable-nacl --enable-offline-auto-reload-visible-only --enable-offline-auto-reload --enable-permission-action-reporting --disable-push-api-background-mode --enable-quic --enable-scroll-prediction --site-per-process --enable-site-settings --enable-spelling-feedback-field-trial --enable-tab-audio-muting --enable-use-zoom-for-dsf=true --enable-webrtc-srtp-aes-gcm --enable-webrtc-srtp-encrypted-headers --enable-scripts-require-action --extension-content-verification=enforce_strict --load-media-router-component-extension=1 --reduced-referrer-granularity --show-overdraw-feedback --top-chrome-md=material --enable-features=AnimatedAppMenuIcon,AutofillCreditCardBankNameDisplay,AutofillCreditCardLastUsedDateDisplay,AutofillUpstreamRequestCvcIfMissing,AutomaticTabDiscarding,BackgroundVideoTrackOptimization,BlockTabUnders,BrowserTouchBar,ContentFullscreen,CreditCardAutofillTouchBar,DialogTouchBar,DoodlesOnLocalNtp,EnableHtmlBaseUsernameDetector,ExpensiveBackgroundTimerThrottling,FeaturePolicy,FullscreenToolbarReveal,HttpFormWarning,ImageCaptureAPI,MacMDDownloadShelf,MacSystemShareMenu,MacV2Sandbox,MaterialDesignBookmarks,MediaRemoting,NativeNotifications,NewAudioRenderingMixingStrategy,NewRemotePlaybackPipeline,NoScriptPreviews,NoStatePrefetch,OmniboxDisplayTitleForCurrentUrl,OmniboxSpeculativeServiceWorkerStartOnQueryInput,OmniboxUIExperimentShowSuggestionFavicons,OneGoogleBarOnLocalNtp,OptimizationHints,OriginTrials,OverflowIconsForMediaControls,ParallelDownloading,PermissionsBlacklist,SafeSearchUrlReporting,ScrollAnchoring,ServiceWorkerPaymentApps,SoundContentSetting,SpeculativePreconnect,SpeculativeResourcePrefetching,TabStripKeyboardFocus,TabsInCBD,TopSitesFromSiteEngagement,UseGoogleLocalNtp,UseModernMediaControls,UseNewAcceptLanguageHeader,VibrateRequiresUserGesture,WebPayments,WebPaymentsModifiers,WebRTC-H264WithOpenH264FFmpeg,brotli-encoding,fill-on-account-select,stop-in-background,top-document-isolation --flag-switches-end

Thanks! That explains it then. Closing as WontFix, since there's nothing for us to do.
Note the red warning on top of chrome://flags/: These flags often trigger features which are still in development, and just don't fully work yet, like in this case. So play with them at your own risk ;)

alright.
reverting that to default