Deno LSP doesn't complain about importing nonexistent symbols, is this a bug?

[dandv]

Not sure if I'm doing something wrong here, but I don't see any error in IDEs running the Deno LSP and editing this file:

import { nonexistent } from '@anthropic-ai/sdk/src';

const messageCreateParams: nonexistent = 3;

console.log(messageCreateParams);

(deno add npm:@anthropic-ai/sdk)

As a sanity check, the LSP works if I introduce a clear error:

deno check flags the error:

$ deno check deno-anthropic.ts 
Check file:///home/dan/prg/claude-in-spreadsheets/helpers/deno-anthropic.ts
error: Uncaught Error: Unable to load /home/dandv/.cache/deno/npm/registry.npmjs.org/@anthropic-ai/sdk/0.33.1/src.d.ts: No such file or directory (os error 2)

Am I doing something wrong, or is this a bug with the LSP?