OpenGrok 1.13.+ ceases to respond several times a day (freezes)

[shusterboris]

I attempted to migrate OpenGrok from version 1.8 to 1.13.25 and encountered an issue where OpenGrok freezes several times a day. At the same time, the suggester also stops working for certain projects (service returns response 200 and empty result's list). I suspect this issue is related to the size of the projects, as everything works fine for smaller ones.
In the logs, I repeatedly noticed Heap OutOfMemory errors from the Suggester just before OpenGrok hangs. Additionally, I saw log entries like the following:

22-Jul-2025 12:49:49.380 INFO [http-nio-8080-exec-6] org.opengrok.suggest.SuggesterProjectData.incrementSearchCount Cannot increment search count for term full:o_engine in '/opengrok/data/suggester/proj13', rebuild in progress.

These messages appear after the reindexing of the project is launched and continue for several hours until the system freezes.
It seems that the suggester is unable to complete its work and continues running until it exhausts the available memory. However, the suggester files do exist and appear to be the correct size. I have several similar projects (slightly smaller), and they do not exhibit this issue.
The project is running inside a Docker container on a VM with an 8-core CPU and 64 GB of RAM, using Red Hat 8.
I am using docker-compose like this.

services:
  opengrok:
    container_name: opengrok
    image: opengrok/docker:1.13.25
    ports:
      - "8080:8080/tcp"
    environment:
      SYNC_PERIOD_MINUTES: '0'
      INDEXER_OPT: -s /opengrok/src -d /opengrok/data -P -G -W /opengrok/etc/configuration.xml -R /opengrok/etc/readonly_configuration.xml  --progress -q -U http://localhost:8080 --webappCtags on -c /usr/local/bin/ctags -R /opengrok/etc/readonly_configuration.xml
      CATALINA_OPTS: -Xms8g -Xmx60g
      JAVA_OPTS: -Xms2g -Xmx8g -Dsun.io.useCanonCaches=false -server
    volumes:
       - '/home/opengrok/src/:/opengrok/src/'
       - '/home/opengrok/etc/:/opengrok/etc/'
       - '/opengrok/data/:/opengrok/data/'
       - '/fs/versions/versions/:/kns/'
       - '/fs/Proj12:/P12/'
       - '/fs/Proj13/:/P13/'