Undefined variable warning can appear when using 95th percentile graphs

[rprofijt]

Describe the bug
After upgrading to 1.2.10 (from 1.1.38) we get these errors in the cacti log:

2020/03/11 11:28:24 - CMDPHP PHP ERROR NOTICE Backtrace: (/graph_json.php[159]:rrdtool_function_graph(), /lib/rrd.php[1586]:variable_nth_percentile(), /lib/graph_variables.php[449]:nth_percentile(), /lib/graph_variables.php[33]:rrdtool_function_stats(), /lib/graph_variables.php[140]:nth_percentile_fetch_statistics(), /lib/graph_variables.php[153]:CactiErrorHandler())
2020/03/11 11:28:24 - ERROR PHP NOTICE: Undefined index: values in file: /opt/cacti/cacti-prod/lib/graph_variables.php on line: 153

To Reproduce
Steps to reproduce the behavior:

Open/render a graph with 95th percentile and nan values.

Expected behavior
Render the empty broken graph without PHP errors

[TheWitness]

Update the graph_variables.php from the 1.2.x branch and let us know if this is fixed.

[rprofijt]

Fixed, thanks!

[a-vasilishin]

I have the same problem. Cacti 1.2.10 download via copy/paste graph_variables.php from the 1.2.x branch.
2020/03/26 19:14:05 - CMDPHP SQL Backtrace: (/graph_json.php[159]:rrdtool_function_graph(), /lib/rrd.php[1586]:variable_nth_percentile(), /lib/graph_variables.php[476]:nth_percentile(), /lib/graph_variables.php[33]:rrdtool_function_stats(), /lib/graph_variables.php[84]:rrdtool_function_fetch(), /lib/rrd.php[899]:boost_fetch_cache_check(), /lib/boost.php[272]:boost_process_poller_output(), /lib/boost.php[629]:db_fetch_cell(), /lib/database.php[383]:db_fetch_cell_prepared(), /lib/database.php[399]:db_execute_prepared())

Update: apache restart and problem gone