Longman Dictionary of Contemporary English
teething troubles
noun
EXAMPLES FROM CORPUS
▪ A hospital spokesman admitted there had been teething troubles.
▪ After early season teething troubles, it also proved a threat to the pre-eminence of Senna's McLaren Honda.
▪ Apart from teething troubles no major problems were expected.
▪ I would like to hope that these are teething troubles, but I remain to be convinced.
▪ Mr John Morgan, the driver, said the machine had sheared its mounting bolts but the problems were teething troubles.
▪ The Class 89 was notable for its lack of teething troubles, sadly not experienced by the two other new electric designs.
▪ These are teething troubles, the shock of the new.
Wiktionary
teething troubles
n. (context idiomatic English) Small problems such as are to be expected with some any new and untried system or product.