NPE in plaintext_from_html

[afandian]

Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  [async-thread-macro-6] ERROR event-data-percolator.queue - Exception processing queue message: java.lang.NullPointerException
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation_types.html$plaintext_from_html.invokeStatic(html.clj:15)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation_types.html$plaintext_from_html.invoke(html.clj:9)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation_types.html$process_html_content_observation.invokeStatic(html.clj:53)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation_types.html$process_html_content_observation.invoke(html.clj:48)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation_types.content_url$process_content_url_observation.invokeStatic(content_url.clj:38)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation_types.content_url$process_content_url_observation.invoke(content_url.clj:19)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation$process_observation.invokeStatic(observation.clj:56)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.observation$process_observation.invoke(observation.clj:44)
Apr 26 08:21:08 10b01792093e percolator-process-prod.3.v5cccjko71mny195pbtgg6npr:  	at event_data_percolator.action$process_observations_candidates$fn__12655.invoke(action.clj:50)