Children's services at Gloucestershire County Council were rated "inadequate" in June 2017, with inspectors finding that poor-quality support for children and families was leaving vulnerable children at risk.
A recent monitoring visit to check on progress found some improvement but inspectors said children in need of help and protection continue to experience delay "at every point of their involvement with children's services".
"Some children remain in situations of unassessed risk for too long, and others experience chronic neglect or continue to be exposed to risk without effective action being taken to protect them, this is particularly the case for young people experiencing or at risk of sexual exploitation," a letter summarising the findings states.
Ofsted said the local authority has been successful in recruiting suitably qualified and experienced social workers and managers.
Meanwhile, the majority of social workers now have manageable caseloads and the number of children without a named social worker has decreased.
However, in some parts of the service social workers were found to not always have the level of skills and experience required to provide effective interventions for children's complex needs.
While managers' oversight of practice and staff supervision was found to be regular, managers are not yet providing staff with sufficient challenge or direction and too often fail to address deficits in practice.
"[Gloucestershire] has taken appropriate action to address some areas for development identified at the previous monitoring visit," the letter states.
"Senior leaders have recently implemented a wide range of improvement frameworks and these have been well supported by significant financial investment and additional resource in children's services.
"However, this investment is too recent to demonstrate improved services and outcomes for children and, overall, the pace of change remains too slow.
"Necessary changes of senior leadership within children's services following the findings from the inspection in March 2017 have contributed to this delay."
Richard Boyles, cabinet member for children and young people at Gloucestershire County Council, said: "Our biggest concern is that the pace of improvements is still too slow and children in need of protection continue to experience delays. We also know that social work practice is inconsistent, but we are addressing these concerns.
"To change this we are invested in staff, reducing caseloads and improving the systems we use. We are working hard to ensure that children in Gloucestershire are protected and this latest report gives us a clear focus before the next visit in May."
As part of its improvement plan, the council has appointed a new permanent director of children's services, Chris Spencer, who will take up the role on 5 March.
Spencer, an educational psychologist and former teacher, has held senior positions at Redbridge, Hillingdon and Slough councils.