getting some new errors and in plentitude. I realize this has to do with custom-ui, so no core issue, though the issue seems to be the entity is not available, where this was no issue whatsoever before.
please check if anything can be done with this:
Log Details (ERROR)
Logger: frontend.js.latest.202006032
Source: components/system_log/__init__.py:209
First occurred: June 10, 2020, 11:52:29 PM (642 occurrences)
Last logged: June 10, 2020, 11:52:39 PM
https://hdomain.duckdns.org:8125/local/lovelace/resources/custom-ui/custom-ui.js?v=20200528-1:31:37215 TypeError: undefined is not an object (evaluating 'entities['sensor.me_picture'].state')
https://hdomain.duckdns.org:8125/local/lovelace/resources/custom-ui/custom-ui.js?v=20200528-1:31:37215 TypeError: undefined is not an object (evaluating 'entities['sensor.wife_picture'].state')
https://hdomain.duckdns.org:8125/local/lovelace/resources/custom-ui/custom-ui.js?v=20200528-1:31:37215 TypeError: undefined is not an object (evaluating 'entities['sensor.daughter1_picture'].state')
https://hdomain.duckdns.org:8125/local/lovelace/resources/custom-ui/custom-ui.js?v=20200528-1:31:37215 TypeError: undefined is not an object (evaluating 'entities['sensor.daughter2_picture'].state')
https://hdomain.duckdns.org:8125/local/lovelace/resources/custom-ui/custom-ui.js?v=20200528-1:31:37215 TypeError: undefined is not an object (evaluating 'entities['sensor.ha_available_version'].state')
apparently 2 of my 4 daughters are fine 
seems to me that during startup these entities might to yet be initialized and some other internal HA process tries to manipulate these (the custom-ui)
also, I get to see this for the first time:
Log Details (WARNING)
Logger: homeassistant.core
Source: core.py:280
First occurred: June 10, 2020, 11:55:25 PM (1 occurrences)
Last logged: June 10, 2020, 11:55:25 PM
Something is blocking Home Assistant from wrapping up the start up phase. We're going to continue anyway. Please report the following info at http://bit.ly/2ogP58T
and when tryin to go to that address it is a closed topic… now where to post?
it is quite an extensive list I am afraid…
life360, sensor.filesize, input_select, notify.mobile_app, sensor.asuswrt, cast, tradfri, hue, script, feedreader, binary_sensor.cloud, rest_command, device_tracker.mobile_app, hassio, speedtestdotnet, input_datetime, camera.browser_mod, sensor.tradfri, onboarding, binary_sensor.threshold, sensor.mobile_app, sensor.waqi, sensor.statistics, recorder, media_player.sonos, owntracks, sensor.gdacs, webhook, sensor.buienradar, sensor.afvalwijzer, timer, logger, binary_sensor.synology_dsm, weather.darksky, auth, sensor.time_date, geo_location.usgs_earthquakes_feed, plugwise, alert, media_player.plex, switch.wake_on_lan, binary_sensor.ping, airvisual, gdacs, frontend, input_text, sensor.nmbs, sensor.template, tts, light.group, logbook, group, media_player.spotify, websocket_api, zone, alarm_control_panel, automation, sensor.command_line, device_tracker, search, media_player.panasonic_viera, air_quality.airvisual, binary_sensor.sun2, sensor.github, sensor.eventsensor, sensor.browser_mod, history, notify.file, ios, binary_sensor.stookalert, binary_sensor.meteoalarm, system_health, media_player, notify.pushbullet, sensor.speedtestdotnet, notify.group, input_boolean, media_player.browser_mod, homeassistant, media_player.mpd, samsungtv, composite, sensor.moon, camera, binary_sensor.mobile_app, plex, sensor.rest, geo_location, ssdp, proximity, switch.plugwise, weather, stt, scene.homeassistant, sensor.darksky, sensor.hue, notify, panasonic_viera, cover, system_log, binary_sensor.template, light.browser_mod, lovelace, geo_location.gdacs, binary_sensor.workday, synology_dsm, sensor.systemmonitor, light, config, ipp, sensor.synology_dsm, variable, climate.plugwise, sensor.file, light.hue, http, air_quality, mqtt, person, device_tracker.owntracks, discovery, weather.openweathermap, climate, spotify, sensor, binary_sensor.hue, sensor.sun2, notify.ios, asuswrt, camera.buienradar, binary_sensor.browser_mod, shell_command, sensor.mold_indicator, cover.tradfri, switch.tradfri, binary_sensor.updater, sensor.nederlandse_spoorwegen, eventsensor, scene, alarm_control_panel.manual, switch.command_line, media_player.samsungtv, sensor.uptime, camera.generic, weather.buienradar, switch, light.tradfri, updater, favicon, device_automation, python_script, switch.template, map, persistent_notification, binary_sensor.plugwise, input_number, sensor.openweathermap, binary_sensor.trend, wake_on_lan, browser_mod, mobile_app, zeroconf, api, counter, sensor.plex, alexa, panel_iframe, sensor.waze_travel_time, sensor.min_max, sonos, sensor.plugwise, sun, sensor.here_travel_time, sensor.airvisual, sensor.season, sensor.mqtt, cloud, media_player.cast, binary_sensor, sensor.ios
to 
