Why does revalidateTag work on local build but not in App Platform?

Code: Link

Output is as expected but the page only actually updates after two refreshes on the local build on my PC, and never on the hosted site.

src > app > api > revalidate > route.tsx

import { NextRequest, NextResponse } from 'next/server'
import { revalidateTag } from 'next/cache'

export async function GET(request: NextRequest) {
    const tag = request.nextUrl.searchParams.get('tag')
    revalidateTag(tag ?? "revalidate")
    return NextResponse.json({ revalidated: true, now: Date.now() })
}

src > app > lib > cms.tsx

import type { PortfolioItem, SocialMediaLink } from '@/lib/types.d'
import 'server-only'

const baseUrl = process.env.CMS_API_URL

export const getAllPortfolioEntries = async () => {
    try {
        const response = await fetch(baseUrl + 'portfolio-entries?populate=*', { next: { tags: ['revalidate'] } });

        if (!response.ok) {
            throw new Error(response.statusText)
        }

        const entries = await response.json()

        if (entries === null) {
            throw new Error('No entries found')
        }

        return entries.data as PortfolioItem[]
    } catch (error) {
        console.error(error)
    }
}

Console:

$  curl https://domain/api/revalidate?tag=revalidate
>  {"revalidated":true,"now":16867717638}

$  curl https://localhost:30000/api/revalidate?tag=revalidate
>  {"revalidated":true,"now":16867717638}