K-R says she m. Henry I d'Oilly who d. in 1163. Both CP (XII/2, 364) and Sanders are fairly clear she m. Henry II d'Oilly who d. in 1196:
Maud had (at least) three children, according to CP:
Henry III, dsp. in 1232 (CP, XII/2, p. 364, note (k) )
Margery, elder da. and (eventually in her issue) coh. - CP XII/2, 364)
The unknown younger daughter and co-heir to Henry D'Oilly
Sanders, Baronies p. 54, also shows three children: Henry III, Margery and the younger dau. who is reported to have married Walter de Daventry, but says nothing is known of her.
In Keats-Rohan, DD p. 352, Maud is reported to have m. (2) Walter fitz Robert of Little Dunmow. This is confirmed by Sanders, Baronies p. 129 note (8).who says that Walter d. in 1198; this death date is confirmed by CP (V, 472, note (f) ). However Sanders says Walter m. (1) Maud de Bohun and (2) Maud de Lucy, while CP says Walter married (1) Maud de Lucy with which Keats-Rohan agrees (DD pp. 332 and 950).
On pp. 620-1 of Keats-Rohan's Domesday descendants are a series of articles on the Oilly family and make it very clear that Maud m. Henry I d'Oilly. So I'll go with that. The articles also give the wives of Henry II d'Oilly.
But Rosie Bevan has,
31 May 2003, triumphed with a major resolution of the Oilly convolutions. See her corrections on the FMG site:
http://fmg.ac/Projects/Domesday/