General help

Not a programmer myself but wouldn't having php's Zend X-Debug on be involved with the precision difference?

Or am I getting confused now with 2 persons in this thread with similar issue and servers but not same server - Sebastian

Anyway ... congrats!   You appear to have solved it! Your 'Helpful' icon deserves a big + in it!

'SoS', Ken

Great job Susan and your Team!
You have found what I've been discussing above about env settings: it's time to file an issue into the Tracker, but some few details are still missing.

serialize_precision is set to 17 since https://github.com/moodle/moodle/commit/404ecca3761b2879b12ac2e71eb18f688c5e40ee (MDL-43314) so it looks like in the "Moodle CLI path" that setting is missing for mostly a bug.

100 looks like "arbitrary": could you look into your PHP ini settings for that value?
If your read https://www.php.net/manual/en/ini.core.php, 100 is there for historical reasons but you should read it in your ini settings:

Before PHP 5.3.6, the default value was 100. Before PHP 7.1.0, the default value was 17.

Here is my trial on PHP 7.2 on CentOS 8.1:

# dnf module install php:7.2
# dnf module list php
Last metadata expiration check: 0:00:55 ago on Fri 01 May 2020 10:45:58 AM CEST.
CentOS-8 - AppStream
Name                 Stream                    Profiles                                      Summary
php                  7.2 [d][e]                common [d] [i], devel, minimal                PHP scripting language
php                  7.3                       common, devel, minimal                        PHP scripting language

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled
# php -v
PHP 7.2.11 (cli) (built: Oct  9 2018 15:09:36) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
# php --ini | grep php.ini
Configuration File (php.ini) Path: /etc
Loaded Configuration File:         /etc/php.ini

# grep precision /etc/php.ini
; http://php.net/precision
precision = 14
; When floats & doubles are serialized, store serialize_precision significant
; precision.
serialize_precision = -1

# php -r 'echo "precision = " . ini_get("precision") . "\n";'
precision = 14
# php -r 'echo "serialize_precision = " . ini_get("serialize_precision") . "\n";'
serialize_precision = -1

Why the Moodle hash depends on that value?
It relies on serialize() which relies on __toString() of those "numbers" in the list of the whole Moodle component versions, which unfortunately are a ... float number at least for the main Moodle core version:

$version  = 2020042800.00;

The end solution would be IMHO to cast the version value to a string before hashing it which is independent from any float precision issue - float is evil in any language not actually a PHP issue!

That being said, I could work on it starting even from filing the issue into the Tracker (I've almost write it here ) and find the "best" solution: in the mean time I strongly suggest you to set the PHP serialize_precision to 17 - the same value now hard-coded into Moodle - into your PHP ini setting; just mimic what written in lib/setup.php:

ini_set('precision', 14); // needed for upgrades and gradebook
ini_set('serialize_precision', 17); // Make float serialization consistent on all systems.

For the Tracker issue purposes, would your mind to share here:

1. your CLI comand, w/o any sensitive data
2. the PHP ini settings above in your RHEL 8.2 - just to save my time to install it

? TIA!

HTH,
Matteo