This problem is addressed in PRISMA 2020 (Q6), AMSTAR 2 (Q4) and MECIR (C37-C38). The length of time that systematic reviews take to complete and publish mean that the literature searches are often out of date at the time that the review is published.
Articles that support this problem:
Up-to-dateness of reviews is often neglected in overviews: a systematic review
2014 : Journal of clinical epidemiology
Systematic reviews with published protocols compared to those without: more effort, older search
2018 : Journal of clinical epidemiology
Is the information of systematic reviews published in nursing journals up-to-date? a cross-sectional study
2017 : Bmc medical research methodology
Are systematic reviews up-to-date at the time of publication?
2013 : Systematic reviews
A Cochrane review on brain [18F]FDG PET in dementia: limitations and future perspectives
2015 : European journal of nuclear medicine & molecular imaging
The currency, completeness and quality of systematic reviews of acute management of moderate to severe traumatic brain injury: A comprehensive evidence map
2018 : Plos one [electronic resource]