Source: Michael Fishbane's Biblical Interpretation in Ancient Israel (New York: Oxford, 1988) 93.
Exodus 21:22-25 states the following:
"When people who are fighting injure a pregnant woman so that there is a miscarriage, and yet no further harm follows, the one responsible shall be fined what the woman's husband demands, paying as much as the judges determine. If any harm follows, then you shall give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burn for burn, wound for wound, stripe for stripe."
In this NRSV translation (and many others), there is a fine if the unborn baby dies, but lex talionis if the mother is harmed. But that's not the only way to understand the passage, since the Hebrew is rather ambiguous. The words translated "misscarriage" literally mean "her children will go out," so the pro-life interpretation says that the passage means this: if the child comes out healthy, then there's a fine. But lex talionis follows if the child is harmed in any way.
Fishbane tends to go with how the NRSV interprets the passage, on the basis of ancient Near Eastern parallels: a fine if the child dies, lex talionis for harm to the mother. But he still believes there's an ambiguity: "...it is still unclear whether damages payable upon injury to the mother would cancel those made for the miscarriage or whether there is to be a double penalty for double damages (i.e., the miscarriage being construed as a damage to the child and not the mother)."
I'm not entirely sure what Fishbane is asking, but part of me gets it. Suppose a man hits a woman and she has a miscarriage, but she also loses her life. Does the man have to pay a fine in addition to being executed?
I don't see that as a great ambiguity. Why couldn't he suffer both penalties? But Fishbane believes that ambiguity exists, and he sees it as unresolved. But why is it unresolved, if there were biblical interpreters who sought to clarify biblical texts? Fishbane may appeal to oral tradition as something that answered people's questions about this law, but, if oral tradition existed, then why did exegetes see a need to write clarifications into the actual text?
I'm not sure if this is a good argument against Fishbane, since the fact that some ambiguities remained unclarified does not preclude the possibility that interpreters tried to clarify other ambiguities. But I do wonder why some got clarified and not others.