If just 1 party member is too low of a level compared to the enemies, running away is literally impossible. Here is a screenshot depicting me still stuck in a battle after 97 attempts of running away. 2 of my pets in this screenshot are fully ranked and have primordial gear.
I tested this in The Lost Grove as well and the same thing happened.

Disregard this if it is an intentional feature.

I have also experienced this same issue. Back when we had the spring fest.

Link: https://www.sylestia.com/forums/?thread=14286&page=1#7 Author: Krinadon Time Posted: 5/26/2014 at 3:41 PM It takes into consideration your lowest level pet, not the average. The thought is... your party can only go as fast as the weakest member. So if you have a low level pet, it will slow down the entire party.

Link: https://www.sylestia.com/forums/?thread=14286&page=1#9 Author: Krinadon Time Posted: 5/26/2014 at 4:50 PM There's probably a threshold (and I'm pretty sure there is) of where the chance of running away becomes 0 or 100% (depending on the level difference). So if one of the pets is really low level, you will have a 0% chance to run away. At least, with how it's currently calculated.

Confirmed that this is intentional.

Link: https://www.sylestia.com/forums/?thread=103167&page=1#3 Author: Imperium Time Posted: 7/7/2022 at 10:51 PM [quote=236303] [quote=236324] Confirmed that this is intentional.

So something like "a chain is only as strong as its weakest link", I suppose