Timelion reads the index pattern field list from the index pattern saved object. This happens to work because its filters for scripted fields but this is considered unsupported and may change in the future. Instead use the index pattern service to load the index pattern.
src/plugins/vis_type_timelion/server/series_functions/es/index.js:122
Related to removal of the index pattern field cache - #82223
Timelion reads the index pattern field list from the index pattern saved object. This happens to work because its filters for scripted fields but this is considered unsupported and may change in the future. Instead use the index pattern service to load the index pattern.
src/plugins/vis_type_timelion/server/series_functions/es/index.js:122Related to removal of the index pattern field cache - #82223