Can ESD from a person damage circuitry even though it was not perceivable?
It is very easy to damage a circuit with ESD WITHOUT EVER DISCHARGING ANYTHING.
A simple experiment demonstrates this.

Wash your hair and let it dry.
Blow up a balloon.
Rub the balloon against some fur (or your own hair, but the purpose is to show that you can transfer static charges without touching the thing that holds static.
Once you have charged the balloon on the fur, stand in front of a mirror and slowly bring the balloon towards your dry hair.
You will see your hair attracted towards the charged balloon. The charge holder (balloon) has induced an opposite static charge into the hair simply by being near to the hair.

If you -- or anything with a static charge -- comes 'near' another object that is even partially conductive, an opposite charge will be induced in that object. Whether or not that induced charge can damage the device depends on the induced voltage and how much energy is contained in the combined induced charge and voltage.
For TTL circuits this was not usually a problem.
For CMOS circuits in their 12v and 5v incarnations, this induced charge was not typically a problem. Usually direct contact was required for a damaging discharge.
For 3.3 volt, and lower voltage devices, however, this induced charge can and sometimes does damage devices without you ever needing to touch the device.  The charge induced on any part of the device will further induce charges on parts near to that and so on in cascades that can be well removed from any part of the device &quot;near&quot; the original induced charge.  If the induced charge at any of those locations exceeds the insulation around that location -- air gap, semiconductor material, etc. -- electricity will flow. If the charge is sufficiently energetic, it will damage something.
To prevent this --

Wear a static wrist strap, AND
Make sure that wrist strap is correctly attached to a static-suppressing work area, e.g. an anti-static mat on your table, AND
Make sure the anti-static mat is correctly grounded to the building/work-area ground, AND
Make sure the device ground -- and device power if device is not operating -- is ALSO attached to that anti-static mat, AND
Use chairs and wear clothing that minimize generation of static, AND
REQUIRE anyone who approaches to ALSO put on a static wrist strap and attach to the same anti-static mat BEFORE letting them anywhere near the device(s).

This might seem like overkill.  And for inexpensive parts or equipment it probably is.  BUT the first time you fry a multi-thousand-dollar piece of equipment without knowing why, it will in hindsight not seem like overkill after all.
You can -- in an emergency DO NOT DO THIS AT HOME I am a registered Professional Engineer who works with electricity and electronics and even I try to never use this method -- put down aluminum foil on your desk, and use an alligator-clip to connect the foil to the ground in an outlet -- VERY HAZARDOUS AND LIKELY TO GET YOU KILLED IF YOU DON'T KNOW EXACTLY WHAT YOU ARE DOING -- and then always make sure you are touching the foil and that you also attach an alligator clip from the foil to a common ground on the electronics.
Other examples of static transfer with no contact:

Bend water -- https://www.wikihow.com/Bend-Water-with-Static-Electricity
Static induction -- https://en.wikipedia.org/wiki/Electrostatic_induction
Pick up things without touching them -- https://www.msichicago.org/science-at-home/hands-on-science/static-cling/