Algolia highlights the first 50,000 characters of the whole result set (or 5,000 logograms for CJK languages). This limit ensures a fast response time for the end user even with large results. You can find more details in our Highlighting documentation.
If your records contain very large attributes, then the 50,000 character limit on highlighting may impact results closer to the top of your results set. To avoid this we recommend making smaller records and breaking up large attributes across several records as needed. You can find guidance on indexing long documents in this documentation.