Somehow on certain entities quantity field happens to have bad data, e.g. see:
https://www.wikidata.org/wiki/Special:EntityData/Q1427761.ttl?flavor=dump
The quantity field on P1083 is "+16100\n" which is obviously wrong. Same in JSON:
https://www.wikidata.org/wiki/Special:EntityData/Q1427761.json
There's quantity field:
"snaktype": "value", "property": "P1083", "datavalue": { "value": { "amount": "+16100\n", "unit": "1", "upperBound": "+16100\n", "lowerBound": "+16100\n" }, "type": "quantity"
This is obviously not correct and API should catch this and fix the data.