Steps to reproduce:

• Create a host "Host"
• Create an item named "Key"
• Set history duration 365d, disable trends
• Import very sparse data (0 to 1 change, keep for 1h then 1 to 0 change, keep for 23 hours, repeat for 30 days)

(host="Host"; key="Key"; meaDate="$(($(date +%s)-86400*30))"; while [ "$((${meaDate} < $(date +%s)))" = "1" ] ; do echo "${host} ${key} ${meaDate} 0"; echo "${host} ${key} $((${meaDate} + 1)) 1"; echo "${host} ${key} $((${meaDate} + 3600)) 1"; echo "${host} ${key} $((${meaDate} + 3601)) 0"; let meaDate=meaDate+86400; done) | /usr/bin/zabbix_sender -z 127.0.0.1 --input-file - --with-timestamps

• Go to Monitoring -> Latest data
• Select "graph"
• Select time range now-97h till now-95h, press "Apply"

Result:

• Most of the time this will just display a line at 0.5 with a yellow ribbon around from 0 to 1, graph completely useless
• Pressing apply multiple times (without changing any graph settings) will at some point show a graph with a change from 0 to 1 on the left side and back 1 to 0 more on the right side, that is useable as you can see that e.g. at 18:08 the signal changed 0-1
• Pressing Apply again will show the broken graph again
• Pressing Apply more times might give you the useful graph again after 3 or more tries
• Using a different data selection expression for the same data, e.g. by using the buttons around "Zoom out" to go forward and back again, then "2023-03-14 17:57:55" till "2023-03-14 19:57:55" is selected (the same 2h as with the now-97h ... expression before) but here the graph is always useless, no matter how often you press "Apply".

Expected:
The same graph is shown every time when the same data is selected using "Apply"

Apart from reproducible behaviour it would also be nice if always a useable graph would be displayed, showing the 0-1 change and 1 hour later a 1-0 change not a line at 0.5 over the whole two hours.