Juxtaposition of adverbials with similar forms should be avoided if one of them is relatively peripheral to the sentence, as shown:
1a. ? 她伸出手在拥挤的人群中（positional adv.）在那个扒手的背上（positional adv.） 狠狠地（manner adv.）抓了一把。
?Tā shēnchū shǒu zài yōngjǐ de rénqún zhōng zài nàge páshǒu de bèishang hěnhěn de zhuā le yī bǎ.
1b. 在拥挤的人群中（positional adv.）她伸出手在那个扒手的背上（positional adv.） 狠狠地（manner adv.）抓了一把。
Zài yōngjǐ de rénqún zhōng tā shēnchū shǒu zài nàge páshǒu de bèishang hěnhěn de zhuā le yī bǎ.
(Among the crowd of people she held out her hand and ferociously scratched the back of that pickpocket.)
(1a) is questionable, because the two adverbials with the same form and semantic role of position are juxtaposed. Between them, the first one ‘zài yōngjǐ de rénqún zhōng’ (among the crowd of people) is peripheral as opposed to the second one, which specifies the location where the action of scratching takes place. So it can be transposed to the initial position as a sentential adverbial qualifying the whole sentence. Thus if a predicate adverbial and a sentential adverbial are required in one clause, the latter would normally take the initial position.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.