Arh yes, spurious images or WTF I am getting this reading? measurement certainty & repeatability, probing techniques and effective bandwidth of the total measurement system even correct VTB & HTB all basic stuff, but at one time or another I suspect it has caught all of us out to a greater or lesser degree. Myself on more than one occasion and it's easy to overlook if your just starting out with electronics with your first scope. Been there done that, have the T shirt, video rights etc

Just be aware that the flying lead on a basic divide by 10 probe isn't always your friend

and yet it is possibly the most used probe in the scope accessory box. It’s the most practical and easy to use as well.
Just make sure you have calibrated the scope via the on board cal ports and get that square wave looking well square lol, check both scope & probe bandwidth remember have a 500Meg scope and 200Meg probes may not be ideal for looking @ 275Meg signals.
As the chaps have pointed out you do have the 'benefit' of a free small loop antenna with your passive probes, great for reaching to those reference points no obvious but farther away from the desired real world measurement result. If possible, use the spring clip on the probe tip it will reduce errors and improve repeatability of the measurement. Its a simple tip but its imho an essential one.
I'm lucky we have many types and ranges of probes so yes, I can obtain a more accurate repeatable result, however each of those probes has their own set of rules and calibration that if not followed will deliver false results to.
I built a couple of test boards for the apprentices we have now working with us, like a scope demo board but with more going on. One of the exercises is measuring a specific rise time and voltage with three different probes plus one specific exercise with and without the flying lead attached to a PP023 passive. The number of questions asked as to why is it so different?
It’s just awareness of the measurement situation you find yourself in, it’s just experience sometimes give you that edge. Otherwise sharing your results with a likeminded colleague who you can bounce ideas off is also a great way to crack that nut.
Ground bounce, thats another can of worms at the start, another day topic I feel
