Cities are updated about once every month on CityStrides.
If you visit the city page, you can see when it was last updated.
To clarify Henrikās explanation -
The changes you make in OSM are implemented in different ways to Citystrides.
The VISUAL map you see when checking your lifemap is an OSM map distributed by Mapbox, so the appearance of the map will update as soon as Mapbox updates their data based on the OSM data.
The NODE information is local to Citystrides. @JamesChevalierās code looks at the OSM data, parses it and then processes the userās runs based on that information. That update is a bit server-intensive since it has to re-check every single CS userās data to make any adjustments to what they have or havenāt completed. For this reason, it does a few cities at a time and goes through a cycle of every city in the world covered by Citystrides as often as it is able based on how long it takes to re-process them (more changes or more users in a city might require more load/longer processing time)
So while your change is indeed almost immediate in OSM, there is some delay between when the OSM change is complete and it is fully reflected in CS