database is locked

Error: database is locked
    at get size (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/sqlite-cache-store.js:298:47)
    at #prune (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/sqlite-cache-store.js:270:14)
    at SqliteCacheStore.set (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/sqlite-cache-store.js:238:16)
    at CacheHandler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/interceptor/cache.js:159:19)
    at Handler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/utils.js:263:40)
    at Handler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/utils.js:263:40)
    at Handler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/interceptor/response-retry.js:202:20)
    at Handler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/utils.js:263:40)
    at Handler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/interceptor/dns.js:22:11)
    at Handler.onComplete (file:///usr/src/app/node_modules/@nxtedition/nxt-undici/lib/utils.js:263:40)

Something with the SQL database? I guess prune should at least catch and ignore the error?

Start with node_modules/@nxtedition/nxt-undici/lib/sqlite-cache-store.js, especially set, #prune, and get size at the stack-trace locations. Trace how a locked SQLite database is handled and clarify whether prune should catch and ignore this error; done means the intended behavior is verified without the reported failure escaping.