TypeError: Cannot read properties of undefined (reading 'getTopBlocks')

[mhsmith]

This sometimes appears when the builder first loads:

TypeError: Cannot read properties of undefined (reading 'getTopBlocks')
    at BlockSerializer$$module$build$src$core$serialization$blocks.clear (chunk-6OVJ3HQQ.js?v=0ab9ef60:5640:29)
    at Object.load$$module$build$src$core$serialization$workspaces [as load] (chunk-6OVJ3HQQ.js?v=0ab9ef60:2969:34)
    at BuilderModel.load (builder-model.ts:97:36)
    at call0 (micropython.mjs:1:74068)
    at micropython.wasm:0x35eb8
    at micropython.wasm:0x1135d
    at micropython.wasm:0x113e7
    at invoke_iiii (micropython.mjs:1:78531)
    at micropython.wasm:0x28403
    at micropython.wasm:0x179cf