The work logs truncation is caused by the JIRA Rest API limitation that Performance Objectives app uses. The app just popup a warning message when such anomaly is detected and it identify the impacted issues.
Unfortunately as soon as the app does not export Clients data on 3rd party data platforms (and aggregate them there) we need to obey all rules that are applied over the Atlassian API but on the other hand that keeps our solution 100% GDPR and CCPA safe.
The app performance depends on number of issues that are analyzed in real time to track particular KPI. It does NOT extend client JIRA systems with custom fields and does NOT store data outside your premises. That’s important to be noticed!
The complete work logs might be extracted only if the app sends separate HTTP requests for each issue and in the case of 10 000 issues it will have significant and unacceptable performance impact and even might risk to be seen as DoS attack from the Atlassian servers.
To help users get accurate data for time tracking goals the app detects such cases and provide link reference with impacted JIRA issues. The users then have the option to merge some of the work logs and get the desired view without impacting the performance.
You may check more on the topic with Atlassian official statement here and here and was introduced by Atlassian to resolve case “Adding worklogs to issues with large histories is very slow” tracked here.