Webhooks stopped to send correct body yesterday

Since yesterday, our Bitbucket webhooks POST bodies without content. It seems we get the unmerged the field variables instead. We receive things like:

200 174 "-" "Bitbucket-Webhooks/2.0" "{\x22push\x22: {\x22changes\x22: [{\x22forced\x22: false, \x22old\x22: {\x22name\x22: \x22master\x22, \x22links\x22: {\x22commits\x22: {\x22href\x [...]

Of course it completely broke our auto deployment