Public holidays separates two weeks sprint
I have planned a release that consists of four two-week sprints. During my planning, I found out that we will have a public holiday (one week) during one of the sprints. This means we will start the first week of the sprint, then have a one-week vacation, and then resume the sprint. Is that OK? Or do I need to replan to avoid that?
How are you planning to get empirical feedback on increments of usable quality in each of your Sprints? That's of more concern than how you choose to handle exceptional situations.
This is my opinion because the Scrum Guide says nothing about this. Remember, that Scrum is a framework not a process. So, this is just something that your team needs to figure out. If it is something known, then the team should just plan for it. Let them decide if they want to split the sprint across the holiday (i.e week 1 of the Sprint, 1 week of holiday, week 2 of the Sprint) or just have that Sprint consist of 1 week of work and keep the established boundaries.
Just let the team decide what is best. They are the ones responsible for the work that is going to be done.
Since there will be a holiday in between, interfering with the duration of other sprints in order to save that sprint from the holiday will disrupt your metrics. If a four-week sprint coincides with a week of vacation, it would be reasonable to plan a sprint based on the remaining three weeks. It's a good idea to discuss this option with your team and stakeholders to assess feasibility and ensure alignment with project goals.